I have fibro, also a little carpal tunnel, diagnosed with nerve conduction tests, which I think is worse when the fibro is flaring. Wearing a wrist brace at night seems to stop it from getting worse.
I get bad pain in upper arm at top of biceps, also shoulder pain right at the tip which is caused by tendonitis and bursitis, diagnosed with MRI. This gets worse when I use the arm for even a few minutes of not very hard work like raking. This seems worse during a flare also.
Today I can't lift a cup of coffee into the microwave mounted in the wall over the oven. I know better than to not move the arm though, as I don't want to end up with frozen shoulder! I first tried every anti-inflammatory with no positive results at all. PT made it worse! Pain meds are no cure either. I've had 3 sets of steroid injections, two of which helped a lot, then I use the arm for a few minutes and it'a all back. I see the doc soon, but usually they don't want to give more than 3 steroid injections, so I don't know what will be suggested.
I don't think fibro causes these problems, but it may aggravate and cause more sensitivity to the pain of the existing conditions.