First time trigger shot—cramps in ovary?

I had my follicle scan done on Wednesday—4 days ago. I had one large 19mm follicle on the right side, with several small ones. On the left side, it just looked like several small-medium follicles....they didn’t even measure those.

Since the trigger shot, my left ovary area is cramping a lot! Lots of pressure, back pain on that side, fullness, etc. To me, it looked like some of the follicles were around the 10mm size range (based on previous scans showing 10mm follicles).

Why is my left side cramping if only my right side had a dominant follicle? Is it possible another could have caught up on the left side too?

I am 4 days past trigger and my tests (opk and HCG) are still extremely dark. I took the Pregnyl 10,000 unit shot.