I am a prenatal yoga teacher, you can try the following as long as you are comfortable: try getting on your hands and knees just as a temporary relief to take the pressure off the back (which is likely where the nerve is, I am assuming ;). Also, if you are less than 34-36 weeks along, you can go into this hand and knee position and allow your forehead and chest to come down to the ground encouraging the baby to move towards your head and likely change positions. If you have a regular yoga practice, try downdog or a modification, as long as you don't have high blood pressure or any specifics that may prevent you from inverting (including being more than 36 weeks along). I did prenatal yoga throughout my pregnancy and it helped relieve these sorts of problems SO MUCH! If you can find a prenatal yoga class in your area you could ask the teacher about your specific issue and likely find some specific instruction and relief...best wishes!