Severe abdominal pain

I have had a bad cough for about a week. My nose is like a runny faucet and the phlem/mucus is gross! I have no other symptoms of a cold, no fever, sore throat or anything. It just feels like my nose is dripping down the back of my throat and making me cough. Now after a week of this, my stomach hurts and makes me double over in pain and tears from the coughing. I thought it was just being sore from all the coughing but now it's a constant pain on my left side. Did I strain my muscle? Should I go to the dr and get checked out?