Oh you poor thing. I suffered from terrible back problems while pregnant (and don't want to scare you, but I still do and DD is 11 months old!)

You can't use Nurofen - tablets or the gel. I'm not sure about Tiger Balm but I would be careful, maybe google it. I used heat packs and had a lot of physio. Warm baths helped too. Stretching is great advice. If you can lay on your back for just a bit, bend your knees up and just roll your body and legs from side to side. Pelvic tilts on a exercise ball are great too - a good physio can teach you these.