I've had a bad cough and tight chest for months have had antibiotics cough meds but nothing works doctor thinks its my asthma but its getting worse?

Chronic Cough. Asthma is best suited for a specialist trained in asthma. Allergists are specifically trained in asthma, especially since 70% of asthmatics have allergies. A pulmonologist can also help. I would start with an asthma specialist.
See a pulmonologist. See a pulmonologist (lung doctor) for further diagnosis and treatment.