Help! Hip and back pain

I'm almost 15 weeks and I don't know what I did today. I watch another one year old boy with my daughter most the day and then went to Costco. Didn't do any crazy lifting or anything. But my back and right hip hurt SO bad this evening. I have been limping around trying to take it easy but I'm wondering if anyone has any helpful lower back and hip stretches. If kinda feels like a muscle spasm but I can't get it to stop. It's been hours. Any advice is welcome! Thank you in advance!