Sounds like Pure O or Pure Obsessional OCD although the name is a misnomer since sufferers also have compulsions that can take the form of a constant need to ruminate about certain thoughts or themes. This books is good The Mindfulness Workbook for OCD: A Guide to Overcoming Obsessions and Compulsions Using Mindfulness and Cognitive Behavioral Therapy (A New Harbinger Self-Help Workbook) https://www.amazon.com/dp/1608828786/ref=cm_sw_r_cp_apa_i_USdSCbT2QD388
This one isnt specifically about OCD it tends to be general but this girl knows her stuff helped me out a lot. Hope and Help for Your Nerves https://www.amazon.com/dp/0451167228/ref=cm_sw_r_cp_apa_i_3YdSCbDPJSP0M
These are the gold standard, but more affordable ones will give you similar information if you're on a real budget. Just search OCD workbook and preferably 'ACT' and 'ERP' to ensure you're getting the best info.
Yes totally :) I have Pure O that often manifested in needing to 'check' online about things, and of course I couldn't be panic googling round my friends house, so if I got triggered I was able to hold off. In fact being around people and out and doing things and noticing how your urge to perform compulsions can be acknowledged without being acted upon is a great start for working towards recovery.
If you can notice your ability to not check/obsess etc around other people you can start allowing yourself to not perform compulsions in private too. That's how I started getting better - noticing how I was able to sort of absorb the compulsive feelings in public and practising that in private!
Well, if you're getting painful physical sensations that are about a genuine medical problem, then you need to see a doctor about the medical problem, and ask if they can help you with painkillers or such.
If you're getting physical sensations that are just uncomfy but you're not actually sick/injured, then you maybe need some mindfulness and Exposure Therapy together, as self-help or with a therapist. A good workbook for you might be here? : https://www.amazon.co.uk/Mindfulness-Workbook-OCD-Overcoming-Compulsions/dp/1608828786/ref=sr_1_1?keywords=mindfulness+ocd&qid=1552389010&s=gateway&sr=8-1
Doing the rituals is probably what is making you keep noticing the physical sensations. If you can train yourself to resist doing the rituals as much, your brain should re-train to direct its attention more away from the body part that's feeling a problem. A brilliant explanation on how to deal with body-focussed OCD (like swallowing, breathing, blinking, itching, body position etc) is on this therapist's blog - http://www.steveseay.com/sensorimotor-body-focused-obsessions-ocd/
Might be important to try and get a proper diagnosis and help for this OCD, ASAP - it sounds like it's affecting your wellbeing pretty badly if you're suffering this much anxiety and doing compulsive actions for 6+ hours straight. And OCD is a treatable disorder, after all, so there's NO reason you have to keep suffering these unpleasant symptoms.
The type of obsession you're experiencing is VERY common in OCD. It's also one of the simpler ones to recover from, because your compulsions are fairly obvious. The easier you can pinpoint your compulsions, the easier it is to start cutting down on them and thus healing your brain. If you've not read much about this form already, maybe check out some of articles describing it? Like: https://ocdlife.ca/false-memory-ocd-when-the-truth-eludes-you/
The second thing you're asking about, some folks with OCD informally call 'Magical Thinking OCD', because your OCD is giving you the irrational thought that you're somehow psychically, magically able to make things happen with the power of your mind. Except, you can't do this. Nobody can. Skeptic investigators have systematically checked claims from people who say they're psychic, and virtually every case is found to be bogus in the end. No matter how real your OCD feels, you can't make bad things happen just by having thoughts about them. :D Which may be some comfort to you (for about 30 seconds until your OCD tells you to doubt this information too...!).
If you'e never tried treatment for this yet (usually CBT, Exposure Therapy and/or medication), might be a good idea to try now. Untreated OCD tends to get worse over time. You don't want 6 hours of anxious Googling to turn into 8, or 10, or 12, or to the point where you spend the entire day doing it or begin acting in a near-delusional manner (people with this type of OCD have been known to actually turn themselves into the police for crimes they've never committed, and ask to be sent to prison. Usually the police recognise they're suffering from a mental illness and immediately release them, but the experience is pretty stressful for all involved! ) The IOCDF directory i good for finding OCD therapists: https://iocdf.org/ocd-finding-help/how-to-find-the-right-therapist/ or if not in budget for you, try free online self-help resources like Ali Greymon's OCD recovery podcasts: https://www.youtube.com/watch?v=AYi9ehG9iw4 or a good OCD workbook: https://www.amazon.co.uk/Mindfulness-Workbook-OCD-Overcoming-Compulsions/dp/1608828786/ref=sr_1_14?ie=UTF8&qid=1551446082&sr=8-14&keywords=overcoming+ocd
There's definitely an element of learning mindfulness that's key too. Learning to accept the uncertainty of random "terrible" thoughts that pop into your head, learning to not engage with them and letting them pass, etc.
I recommend two books: The Imp of the Mind by Dr. Lee Baer  and The Mindfulness Workbook for OCD by Jon Hershfield and Tom Corboy 
 https://www.amazon.com/Imp-Mind-Exploring-Epidemic-Obsessive... https://www.amazon.com/Mindfulness-Workbook-OCD-Overcoming-C...