Unkown condition at present time

Patient: Having troubles with my chest, have been told it could be asthma but they not 100% sure however my air flow readings tend to be around the 300 mark and tend to drop as low as 250 been given brown inhaler and also the blue along with sort course of steriods but they dont seem to help i am constantly coughing but not bring anything up and feel like i am being strangled a lot of the time blood tests come back normal and only just had an xray but i am unable to sleep or do normal activities

Symptoms: Coughing, wheezing, tight chest,feeling sick