Warm bath, massages, have you tried a heating pad?
If you can see a Chiropractor. I did and was the best thing ever. I'm almost 20 weeks and had awful lower back pain
I have the same thing and am 17 weeks. Try sitting up straight when you do sit and avoid lifting heavier objects, if you aren't taking vitamins they might help and hot bath or hot towel over the lower back. Honestly there isn't a lot of relief for me either but yoga does help
I am 19 weeks tomorrow and I have lower back pain usually after doing a lot of walking. Seems to be on my lower left side and sometimes makes me feel like my left leg goes paralyzed Lol it hurts! But I usually have my hubby rub my back for me, and do a lot of stretching.. it is completely normal to experience back pain at thus point as a lot of things are happening, growing and moving. Good luck!
Take a long warm bath before going to bed and when you get to bed ask your partner to rub it for you if its bad through the day have it rubbed too im 25w and have terrible back pain due to medical reasons I cantttake my medication because of the pregnancy some days I cant get out of bed or move through pain its just one of those things we have to deal with im afraid