The Web resources on muscle strain (the ones I can read before
my screen is covered in popup ads) seem to be concerned
with the first days after an injury. What do you do when you
don't realize you've injured yourself until _weeks_ later? This
has happened to me.

Apparently I strained my right shoulder during our vacation,
carelessly hefting heavy luggage in and out of our vehicle.
A few days into the trip, I got pain that I took to be the transient
bursitis that's afflicted me in recent years (I'm 58). It wasn't
for another week or so that the pain maxed out and I realized what
had caused it. There was no other symptom -- no swelling, etc.,
just pain deep inside the shoulder upon certain specific motions
of arm and shoulder.

It's now a month later, and there's been a noticeable improvement
in the last couple of weeks. Still, it seems like a long time.
I use a heating pad on the shoulder in the morning for an hour
or so. Should I be flexing the affected muscles as well?

Or, if you're going to tell me to go to a doctor, should I start
with the generalist I saw for my biannual physical last year
(I hope he remembers me) or proceed directly to look up a
right-shoulder specialist?...