I presume that any cardiac cause for your symptoms has been excluded; if not, the first thing to ensure is that your symptoms are not of cardiac (heart) origin. Once that has been done, it is possible that you have a stomach ulcer due to your medications and I would advise you to have an endoscopy done to exclude this.
Also, Helicobacter pylori should be tested for at endoscopy and treated if present. As a measure of evaluation, your Haemoglobin should also be checked to make sure that you are not anaemic. Your doctor should be able to examine you and treat any heart failure if present. All the conditions tha t I have mentioned can cause breathlessness.