Omeprazole and shortness of breath

My husband was on Prilosec for several years, and switched to Omeprazole by our prescription plan. I don't know if the medication is the cause, but he started experiencing chest pain, and occasional shortness of breath, not the same as the acid reflux discomfort. He went to the Dr. and was tested by blood tests, EKG and chest x-ray. All were normal, so stress thallium test was ordered. He passed the stress test with no problem, but had a small abnormality on the thallium scan. He was referred to a cardiologist because of this and a heart cath was performed, also normal so thallium scan was a false positive. The cardiologist changed his medication to Nexium. Could this all be due to switching to Omeprazole? I don't know, but the timing is suspicious.

I have been on Omeprazole 20 for six months now. Even though I feel better with my reflux, but when I finish the drug and stop taking it, within two days the refux starts again. When I am taking omeprazole 20, I feel pain in my both arms specially when I extend my arms and I have shortness of breath and some time choking even when I am not eating anythings.