I'm beginning to think that we need to recruit a doctor who specializes in sports medicine and Repetitive Stress Injuries!

Playing guitar uses muscle groups that don't get used,(or at least don't get used the same way), by any other activity.

If you play a lot and then knock off for a while, you lose some of the muscle 'tone'. (The gear isn't the only source of your tone!) The fall-off from peak condition happens fast, but its dangerous to try to come back too quickly.

Don't push too hard. It probably took you a long time to get to the level you have come to regard as 'normal'. It will take a while to get back there.