Yoga and stretching works wonders. Also, use heat, not ice. Ice is just going to make your muscles tense up, not relax. Try the child pose and stretch your arms as far as possible. It makes me feel a thousand times better.
I'm the same way. Im 32 weeks & last night I just wanted to cry it hurt sooo bad. & I was having bh at the same time & they are starting to hurt unlike before.
Ask your doctor first but there are tons of great stretches to relieve low back pain. A lot of lower back pain is actually cause by tight leg muscles so stretch out those legs too! I'm right there with you at 35 weeks and I've just been making sure to stretch in the morning. Hope that helps!