Bad back?

I’m 38+3 and I literally can’t stand up for too long because my lower back is so sore!!!

It started last night but I put it down to walking round doing shopping for 2-3 hours. For better after boyfriend rubbed it and when I was lying down in bed.

I’ve walked maybe half an hour today and stood up doing some ironing for maybe half an hour and I’m in so much pain. I’ve had to stop and sit down for a bit 😩