I have sharp pain under my lower left rib cage, what is it?

Lately I have been waking up with a weird sharp pain under my lower left rib cage. It is a very sharp sudden pain and begins mainly when I am laying on my right hand side but then once triggered it continues for quite some time. Heat helps calm it down the best. I also had random shoulder/arm pain and aching once with it and when I walked around my arm felt useless (left arm). Not sure what is causing this. It is in the area where my sleep would be. Almost one year ago in a college division one soccer game I was kneed directly in the rib cage in the area the pain is. I was told I had a very slight fracture in my rib and bruising but nothing to be worried about. Not sure if this could be connected? Just curious if you’d be able to pin point this a little more to what it could be causing that pain after about a year (I know it is hard with everything it could be). Thanks for your time!