Shortness of breath (SOB) while laying flat can be a symptom of heart failure, however, in someone your age, that would be unlikely, possible, but unlikely. You say you are overweight, but you don't say, by how much. If you are obese, and lay flat, the weight of your body pressing on the lungs can also cause the same symptoms, including the cough. See a doctor and have this looked into.
Thankyou both very much for your anwsers.
Well I have a problem with SOB while laying down. I to have the choking or cough. Well they Diagnosis me with Left Ventricular Diastolic Dysfunction cause by Hyperstention or Diabeties. I also have Pulmonary Hyperstention and Sleep Apnea and they think Mitral Stensios or they Leaking don't know I have other issue with my heart and lung that are playing a part of my SOB while laying down. I would if I was you talk with your doctor and let them know what's going on with you. they can run some test on you to find out why you can't breathe while laying down.
I think you better go to an internist or cardiologist. It's possible that you're having heart failure, fluid is getting backed up in your lungs, and as a result you feel short of breath laying down.
It's also possible there's something else like Pericarditis going on. I've just been diagnosed with that, and I also have some shortness of breath laying flat.
Both of them come with other symptoms, usually, so it's worth checking them. Go see an MD, though.