Heating lad?

So I’m 30+2 and since the middle of my 2nd trimester I have been getting this awful pain in my left side. Most likely muscular, feels like my obliques are being stretched or pulled. It started at night and wakes me up...once I wake up it’s pretty much impossible to go back to sleep. Left side is out of the question and if I lay on my right side I can still feel the stretching feeling. And obv sleeping on my back for too long isn’t recommended. I’ve brought it up to my docs at every visit since it started and none of them are concerned about it, just part of the aches and pains that come with the pregnancy package. But I need some relief. Im getting like 3 hours of sleep combined a night and it’s really messing me up. I read I could use a heating pad on the lowest setting for 10 minutes at a time, as long as it doesn’t raise my body temp it’s ok. I’ve done that maybe 3-4 times since it started, so not much at all. Early this morning I woke up to pee but could feel the start of the pain, so I decided to put 10 min of low heat on it before it got really bad. I wasn’t expecting to fall back asleep but I did, for maybe about 30 minutes. It didn’t stay on me the whole time, when I woke up it was hanging off the side of the bed. I don’t think my temp got too high bc I was in shorts, with the fan on, and not really under the blanket, I had it bunched up like a body pillow. I didn’t feel hot at all. Do you think I should be concerned that the (low) heat was on it for longer than I meant to? Should I call and mention it to the doc?