What Causes Multiple Miscarriages, Cramps In Ovary And Bleeding After Sex?

I ve had painful cramping in right ovary for a few years. Dr told ne this was normal. On third day of my cycle I got horrible cramps and back pain and more bleeding than normal. After period I keep spotting. After sex I bled alot. I m 43 and I ve had three miscarriages in the last two years. What s wrong with me?