I have consistently exercised for more than 30 years. I do a combination of a lot of different activities because I do not want to risk missing out on something that would help to slow down the aging process!! Because of all that work, I have remained mobile and can keep up with people much younger than myself.
About 10 years ago, I injured my shoulder in yoga doing a chaturanga (push up), a common injury for those, like me, who do not keep their elbows close to their body. I was compensating for weak muscles with bad form. I went to a PT and tried some exercises but they did not work. I decided I would have to "live with it". Years later, I talked to a trainer who told me that I needed to strengthen the muscles surrounding the injury. That made sense.
I followed a program using weights and resistance bands and today I am never bothered with any shoulder issues. Doing it right made up for years of doing it wrong.