Could be almost anything, without a sport's doc looksee.....
Wear and tear thru the years could onset that quickly.
A strain or tear could bring it on quickly.
For years, I couldn't brush my teeth with either hand alone, or shave, from wear and tear usage thru the 50 years of sports and injuries. Had to sleep with my arms pinned over my head.
But that's me, old age overuse.
Don't know much about you.