Asthma worse after stopping smoking

Patient: Hi, I m 50 and asthmatic ( since a child) on regular salbutamol and seretide 250. Stopped smoking 8 weeks ago, but have needed 3 courses of 5 day prednisolone since due to several asthma attacks… breathing feels ok in between courses then flares again ( feel very hypersensitive to dust and dogs, but sometimes trigger unknown) had lower lobe pneumonia here back in Feb … three courses of antibiotics to get rid of it but have still had a slight niggly pain here since. Xray yesterday ay A and E ( following two attacks this weekend) shows hyperinflation and very small area of blunt costal margin on one lung ? pleural effusion. No infection, normal blood results.Any idea why this is happening and when my breathing will improve?

Symptoms: SOB, asthma attacks and increased clear mucus, no cough