Not sure how old you are but it took more than 20 years for a knee injury to come back and haunt me. Joint pain and stiffness as we get older is a bitch!
Also, the further I get into my 50s, the more I feel the effects of arthritis that runs in my family.
It seems that what I don't do has more effect on this stuff than what I do.
New pillows on the bed can help with arm pain, depending on how you sleep.
Stretching and simple arm movement exercises can help a lot.
Have you recently stopped doing some activity that uses your arms or, if you spend time at a desk, changed your desk setup? That can cause discomfort.
As far as the bike goes, if you put washers under the risers, make sure the rest of the hardware is long enough.
If you haven't tried rolling the bars back or forward a few degrees, that can make a huge difference. You may not have much room to do that without hitting the tank or windscreen though.
The urge to buy terrorizes