31 weeks pregnant..muscle spasms?

Im 31 weeks pregnant tomorrow and having terrible pain. I started having pain about 4 hours ago. It started in my side and felt like I twisted funny or something. It has since migrated across my belly and now back to mostly the left side of my belly. It's not contractions or braxtom hicks because it doesn't let up at all. It does seem to improve when I lay perfectly still, and it hurts badly to the touch. It does feel muscular, like a charlie horse. I called the doctor and she told me to take two Tylenol, rest, and to call if it gets worse. It hasn't gotten worse but it's not really improving greatly. I can't walk and it is still a very stabby pain. Anyone else experience this? Pelvic muscle spasms?