Same questions & possibilities as the last post, but our answers would be better, wiser & more relevan t if we knew how far along you are rather than us assuming by you mentioning contractions that you'er near to having the baby.
For back pain I used several things, sometimes one after the other, othertimes depending on situation or precise type of pain:
curled up with my back against the warmth of my husband & "felt" his breathing sort of as a gentle massage;
long soak in a hot (not too hot) bath while I read & had a cup of tea;
take a gentle walk;
hot pack against back;
sitting up to sleep;
do something to occupy your mind - sometimes if I forgot it I found that i'd relaxed & it had eased or even gone.