13 Y.O has runny nose and then he swallowed lots of mucis and now he coughs a lot. Any treatment for the coughing and runny nose?

I sympathise... I had that type of cough after christmas 2012. My back even ached from all the coughing. I took mucinex-dm mainly for the dextromethorphan hydrobromide, which is a cough suppressant. It is inexpensive and worked wonders for me! take the maximum recommended dose until your cough tones down.