What to do for this pain?

I work in an office and I was in meetings from 12:30 to 5:30 without getting up. My back was in so much pain. Then I sat in traffic for an hour and between my back hurting so bad and baby constantly kicking it was horrible. Now no matter what position I try to sit on the couch it hurts. It's mostly my lower back down to my tail bone. Have you guys done for back pain?