Do I have heart problems or thyroid problems?!

Do I have heart problems or thyroid problems?

I went to the doctor two weeks ago because I felt pain around my heart. The doctor said it was some joint infection and gave me some steroids. TO make sure it wasn't heart problems, she gave me an x-ray of my chest and everything looked fine. However, I feel the same pain now. I have also been told that my thyroid levels are too high. Is it possible that the doctor diagnosed me with the wrong problem? I'm 17 by the way. thanks.

"Hyperthyroidism is a condition caused by the effects of too much thyroid hormone on tissues of the body. Although there are several different causes of hyperthyroidism, most of the symptoms that patients experience are the same regardless of the cause (see the list of symptoms below). Because the body's metabolism is increased, patients often feel hotter than those around them and can slowly lose weight even though they may be eating more. The weight issue is confusing sometimes since some patients actually gain weight because of an increase in their appetite. Patients with hyperthyroidism usually experience fatigue at the end of the day, but have trouble sleeping. Trembling of the hands and a hard or irregular heartbeat (called palpitations) may develop. These individuals may become irritable and easily upset. When hyperthyroidism is severe, patients can suffer shortness of breath, chest pain, and muscle weakness. Usually the symptoms of hyperthyroidism are so gradual in their onset that patients don't realize the symptoms until they become more severe. This means the symptoms may continue for weeks or months before patients fully realize that they are sick. In older people, some or all of the typical symptoms of hyperthyroidism may be absent, and the patient may just lose weight or become depressed."