22 yr. old chronic joint pains

I started having joint problems when I was 14 or 15.  It started with my knees.  I was diagnosed with patello femoral syndrome.  Surgey was done but didn't help at all.  I was told I had little cartilage in my knees.

During physical therapy, I was told my hips were overly flexible.  PT was done for almost a year for both the knees & hips with no results.  I have learned to live with the knee pain, but I'm 22 now and my hip pain is getting worse.  They are constantly sore, sometimes sharply painful.  The pain is on the outside of my hip.  It also makes a very loud popping noise when I bend over.

At 15 yrs. I started getting shoulder pains.  It was attributed to a rotator cuff injury from softball.  I was given numerous cortisone injections, and PT for 6 months with no results.  I kept getting the cortisone treatments for about a year.  My shoulder still is symptomatic, it gets very weak and painful if I'm doing things over my head (i.e. washing my hair).

Any chance these are all related, if so what?  Any suggestions?  I feel like my body is falling apart.