It could also be the baby kicking your cervix. It actually really hurts. I remember when my first baby did it. I thought I was going into labor! Lol Hope you feel better soon!!
It's the baby putting pressure on things. It's not fun. I know it's painful and annoying but it's a good sign really. :)
I'm 33 weeks as well n feeling the same pain .My doctor told me my baby head is down already n it can come from that as well... I don't know how low she is yet I have a doc appointment this week. I just try n rest whenever I can.
I think it just happens from the pressure of the baby being low. I get it a lot too, and your doctor is right the best thing to do for relief is to put your feet up and rest. Yay for third trimester discomfort, right? Lol hope you feel better soon :)