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.