I am pregnant for 13 weeks and since yesterday I can feel painful at my left side of my tummy. Is it the baby is growing that's why will have this kind of pain?

Yes I had it and could barely walk had to leave work early. For me it was where the baby was lying. Have u a hot water jar or some heat pack to put on your left side and paracetamol. It Will definitely ease the pain and eventually baby will move..

I agree the heat pack can help but more importantly take time to rest and put your feet up and make sure you don't lift or over exert yourself - a few days of no housework is never a bad thing. - If you are concerned though pop to your doctor.