My Husband Went To The ER Yesterday With Chest Pain

My husband went to the ER yesterday with chest pain and breathing problems. They did a ct scan, and xray and did not find anything but suspect he has the flu. Since he came home he has a severe sharp pain on the left side between the collar bone and armpit area. He does have asthma. He has pain all over and his chest hurts when he coughs. They gave him a prescription for the flu symptoms. I am not sure if I should take him in again to the ER since they didn't do anything for him yesterday but the prescription.