It is normal. This is due to stretching of the uterus, baby's growing and limited space within our womb hence with the restrictions, you will feel pain that comes and go. It can also be due to baby kicks,movement, stretching,turning. Nothing to be concern of unless it is persistent pain and you don't feel comfortable. Highly advise to lay on ur left side instead of right side. Both pregnancy, Ive been sleeping on my left side.
You could try pre-natal massage to help relieve the pain.
itsallabout_mytwokids