I am not if it is related to your pregnancy. However, pregnant women can have special foot problems from weight gain, swelling in their feet and ankles, and the release of certain hormones during pregnancy that cause ligaments to relax. These hormones help with child bearing but can weaken the soft tissue structure of the feet.
Your symptoms are consistent with bursitis or plantar fasciitis.
There are several things (such as rest, ice, pain medicine, arch support, weight loss, gel heel pads and many other things) that your doctor may prescribe you to relieve the pain.
Good Luck!