I had a hysterectomy in October 2009 and I'm still having severy abdominal pain after sex, why is this happening?

It sounds like you should consult your doctor and/or GYN. Maybe you haven't healed properly or maybe you have complications which are causing the pain. Or possibly, the acquisition of certain types of STI's/urinary tract infection can cause moderate to extreme abdominal discomfort.

Hope this helps