Call labor n delivery of any hospital if ever concerned or in doubt the will either put u ease or tell u come in, either way better safe then sorry. But I'm 29 weeks n get alota back pain n abdomen pain but its nothing concerning. Good luck
If it comes in waves and has a pattern, I would think it were labor. If its constant, it may be just back pain/round ligament pain. Drink a few glasses of water and sit. Keep track if it's coming in waves, how long it lasts and how far apart it is. Good luck.