Pains, aches and cramps in your belly while you're pregnant are normal. They're usually nothing to worry about, if all is otherwise well.
Carrying a baby puts a lot of pressure on your muscles, joints and veins. This can make you feel uncomfortable around your stomach area.

As your baby grows, your uterus (womb) tends to tilt to the right and the ligament may spasm or contract. So you may feel cramping pain more often on your right side. You may be experiencing this pain and this is common. But if are in doubt please dont hesitate to call your doctor and clear your mind of any fear.
Resting when the pain happens usually eases cramping, along with taking these steps:

Try sitting down for a while.
Lie down on the side opposite to where the pain is, and put your feet up.
Have a warm bath.
Try to relax and take a deep breath

Sometimes, having sex and reaching orgasm can give you cramps and a slight backache. An orgasm makes pulsations ripple up through your vagina and uterus, which can leave a feeling of cramp afterwards.

Having sex when you're pregnant can make these ripples feel more like contraction cramps, particularly in the third trimester. But don't worry, there's no evidence that orgasm sets off labour, even at term.

You could ease potential cramps by taking sex soft and slow.

Watch for clear watery discharge, which may indicate membrane rupture, if this happens go to your doctor immediately.

Regards
Dr Santosh