Looking for tips on sternoclavicular pain occurring from a non-impact injury

[Jlifts]

I had decompression surgery five months ago on my right shoulder. Everything from this surgery seems to be healing fine just some scar tissue to work through, but my question lies elsewhere. In my sternoclavicular joint(rt) I am having pain, which I believe is aggravated by the sternocleidomastoid pulling on the joint (such as tensing up during leg presses at the gym) and some anterior arm extension movements.  This pain started after dancing at a concert (no impact injury). I have been to my Dr and was given a steroid and meloxicam. This seemed to help, but was easily aggravated back into pain. The pain will last a few hours after aggravation, but will completely subside. The pain is a sharp burning sensation. I have been resting my arm very well, but the injury is just so easily aggravated. If I press on on the part of the joint that hurts (superior) it almost feels like a lump moves. Any tips would be very appreciated!