I am older and made a few other discoveries over the years.
Drink enough water, damn most muscle problems caused by insufficient hydration. Now another thing that many guys screw up with. Never stretch a cold muscle. Arnold always recommended and I do religiously 2 light sets of say squats on leg and deadlift days, then stretch.
So get checked out, and get healed.
Stay the hell away from isolation exercises for a while. Do compound moves to strengthen the joints and all connective tissue.
Actually I recommend about 5 exercises for a while. Squats, bench press, deadlift, seated cable rows, shoulder presses in a smith machine, and barbell curls.
Works for us here.