I saw the nurse practitioner with my family doctor today, and all I have to say is "Thank the goddess for general practitioners!"
I went through my spiel about my forearm, how it seems to be related somehow to my chemo cycle but isn't listed as a side effect (well, muscle and joint pain is, as is swelling, but not limited to one particular area, like only a forearm. The breast surgeon, to her benefit, did say that she believed it was related to the chemo and that there are lots of unlisted side effects, especially with taxotere. She had no other suggestions, though.
Turns out it's tennis elbow, made worse by the chemo (we figure that because it gets better and worse with my chemo cycle). I've had issues in the past with my elbow more so than my forearm: when Tynan was 30 lbs and 5 months old and I used my right arm to lift him into and out of his car seat, hold him to nurse him, and carry him; when we owned that big, old, maroon van and the power steering was out. But the pain never radiated down my arm or affected my muscle.
Bad news, depending which surgery option arises, if I don't have the breast on the right side removed, this will be the arm I use for everything and, therefore, may end up needing to waste physical therapy visits on it.
Good news is I have a double mastectomy, I'll have quite some time to rest it. That's what I'm hoping for.
At least I know what it is and have some ideas for relieving the pain.