Try different yoga positions like cat/cow pose where you are on your hands and knees arching your back. There is another where you lay on your back with your butt propped up in something like a phone book and cross one ankle over your knee, hold then switch. It should take the pressure off your back.
I mean I wouldn't know if Im having labour pains but I seen my dr today and he was no help but I have this heating pad but its too hot for a heat pad so I just staying laying down all day until I have to get up
Is it from muscles u think? I have a bad back and have had nothing but ptoblems this pregnancy. I use the hot pacjs u put into the microwave which privides temp relief, i use deep relief its a gel for sore muscles which also provides a bit of relief and is safe to use while pregnant. If ur pain continues u can ask ur doc to refer u to a physiotherapist as well. These are all suggestions as long as its not labour pains ur feeling.
You might phone Labor & Delivery and see if you should get checked. 30 weeks is early for labor, but you never know.