Yes, you can absolutely have RA and fibromyalgia (FM) at the same time - I'm in the same boat. I've had RA for 40 years and developed FM in 2003/2004 and in the beginning, found fibro symptoms much more difficult to deal with an RA symptoms. But we humans are wonderfully adaptive creatures and you learn tips, tricks and medications that help you deal with the symptoms. We are taught to avoid a reliance on medication, but once you develop a chronic illness, you have to reframe your thinking - try to keep in mind that meds are a tool to help you live your life.
One of the interesting things about FM is that medications like narcotics and regular painkillers tend not to work very well for the pain. Instead, they have found that antidepressants can be very helpful. Anti-depressants elevate certain chemicals in the brain, including serotonin and it turns out that low serotonin levels happen not just in depression, but are also associated with pain and fatigue. As well, antidepressants help regulate sleep and one of the symptoms of FM is interrupted sleep cycles (the worse your sleep is, the more pain and foggy thinking you have). I'm pretty sure that the meth doesn't directly influenced fibro, but suspect that if it decreases your RA pain, the tense muscles of fibro might relax a little, too. As well, I'm pretty sure that your doctor wouldn't prescribe Cymbalta if it interacted with meth, but you might want to double check with your doctor and/or pharmacist about that.
Down the road, if you're still experiencing FM pain, there are other medications that may be helpful, such as an overnight muscle relaxant and a medication for nerve pain called Lyrica is also very effective for many. The brain fog may stick around in a less intense form, but you learn ways of dealing with it (e,g., I have Post-Its and a pen in every room of my house). On HealthCentral's menopause site, Toni Hurst wrote a great post about how to manage a foggy head (you can find the article here). Equally important, I've also learned to not care as much as I used to - your brain is still in there and once your symptoms are better managed, a significant part of it will come back.
I also get horrible neck and shoulder pain and found that it is essential for me to keep that area warm, so I almost always wear a sweater or a shawl/scarf - one that's as fashionable as possible, naturally! - and try to not sit directly under an A/C vent (drafts are your enemy!). HealthCentral's ChronicPainConnection has an entire section on fibromyalgia (click here) and you'll be able to find lots of information and other tips there.
Good luck! And please write again if you have any other questions.
thank you for posting this information I have sent the letter to family members to read hoping that they will read it as it explains very clearly that fibro is a real illness and I am not FAKING or wanting attention I am so very tired of pretending that I am ok to everyone when I am NOT. I have been living with this diagnosis since 2004 and just recently was diagnosed with RA on top of having fibro so again thankyou for posting this I can only hope that my family members will come to understand more about the seriousness of these illnessess and believe me when I tell them I am not feeling well. I'm tired of fighting everyday to do simple tasks and I push myself to the extreme so many times a week only to suffer even more.
Jan