Try Osteopathy. In my last pregnancy I could barely walk for 6 weeks. Turns out my pelvis had tilted slightly and she gently worked her magic and within a week I was fine. She then went on to help me prepare for birth and I am sure she had something to do with my quick and drug free labour. Get someone who specialises in pregnancy/birth.

Other than that, if it's just muscular, heat packs are great and you can take Panadol Osteo which is stronger than normal panadol, but can only be taken 6 hourly. Good luck