Sounds like you could have a cyst on your left ovary...
I´ve had a bunch of those, and if you can get your hands on some Naproxen, that helps...
I need to take large doses though. I take 1000mg 3x a day for 3 days...
If you´re not used to Naproxen, a smaller dose should be enough, maybe 500g 2x a day for 3 days...
It´s best to get a diagnosis if possible.
I hope this helps.