Dear Mr. lybrate-user, weight increase could be due to steroid use.
If you are not using steroids as medication, then you need to get your thyroid and a1c levels checked for thyroid & sugar diseases.
Polysomnography is beneficial for sleep apnea patients (who snore a lot), for other cough & breathlessness, pft test is recommended.
Try to be more active, follow a strict diet chart, do regular exercise.
Wishing you good health.