I had this same issue and visited the physiotherapist. She recommended the belt as jcrane9 stated and also kegel exercises. That was around 24weeks... the pain is gone but I still continued the exercise and I no longer need the belt. I will be 39weeks in two days...
I've had SPD (symphysis pubic dysfunction) since about week 24, Dr suggested a girdle/belt that's helped a lot. They can also refer you to a physical therapist to help relieve the pain. I found my belt on Amazon and never needed PT so I definitely recommend it!