I had this problem during my first two preg... dr said it was my siatic(sp?) Nerve being pinched and unfortunately there isn't solid hog can dip other than warm bath and massage the area.. is from you hips moving getting ready for birth..
Try some yoga positions to take the pressure off the tailbone. Also laying on the floor with a firm pillow supporting your lower back and tailbone while I stretched or read for an hour helped for me. Also time in the pool takes pressure off joints.
Ok I'll try that using bubble bath n bubble salt ok
Warm baths and massages. I take on average about 3-5 baths a day because of the pain I have this pregnancy.
I'm 15weeks also Im not sure if you can take anything fir it but if it's bad you should calk your doctor and she what they say. But I hope you feel better