My chest and upper throat is tight i had a blood clot but now gone but i still have trouble breathing. my doctor says my heart and lung are healthy?

Asthma vs globus: The description of the blood clot throws things off a bit, but a tight sensation in that area with healthy heart and lungs in a young person typically is called a globus sensation and is the result of a spasming sphincter muscle at top of the esophagus. Reflux and/or anxiety is the typical cause. Raising the back of your bed so that your chest is elevated slightly higher than your stomach helps.

2nd opinion: This is a problem that requires a face-to-face meeting with your doctor. In that meeting, your doctor will listen to you, perform a throrough examination and possibly order labs or other tests. Based on this information, he/she will be able to tell you what's wrong and what to do about it.