For several weeks I've been having shoulder pain

I went to the chiro (a former bodybuilder) and he suggested that my rotator cup is loose because my anterior deltoid is developing more (from cycling) than the posterior deltoid. Hmmm...talk about the cause/effect of kinesiology

The prescription: Inverted Fly exercises to develop the posterior.

I read all these things that talk about the need to exercise "off the bike", but this is my first tangible brush with the reality.

Does anyone know of other "balance" exercises that are needed to compensate for what the bike doesn't develop?