A.W.
It's probably due to his cold. When little ones get too congested it can come out through their tear ducts. It shouldn't be painful for him, but can be uncomfortable. I don't know if your doctor approved a decongestant like Pediacare, but you can ask. The only reason for a doctor's visit would be if he has a sinus infection, but if you were at the doctor's office yesterday, he should have diagnosed that. I would watch him for a day or two. If he doesn't get better or gets worse, take him back to the doctor.
Good Luck and many prayers!