Why am I experiencing these chest symptoms?

[Delmarie94]

I lift something heavy or participate in moderate activity, and I feel like I've ran 50 miles. My heart races and I feel out of breath and lightheaded. I've been to the hospital where they did Chest X-ray and blood work. They found me dehydrated. Recently I've been diagnosed with Salmonella which I'm taking Ampicillin for. My MD had me do a CT scan which found nothing only calcification in my kidney. She referred me to a neurologist and rheumotologist for positive ANA. When I lay on my left side, the pain feels sharp as if it was on my heart. It felt like spasms in a sudden moment. When I laid on my back, it was difficult to breath in. I also felt the spasm like pain on my right neck and left bottom chest near my arm including on my left back. I went to the hospital numerous times, nothing only some palpitations. Cardiologist performed an Echo, Nuclear stress test, and had me wear a heart monitor. Nothing, only tachycardia like episodes. I have been having anxiety and panic attacks from my stress, but I can tell the difference. I'm so stressed not to know what's wrong. Any advice? I'm 22, 5'5 with a weight of 91 and a non smoker. The only health problem I know is scoliosis. Thank you.

[achillea]

At 5' 5" in height and weighing 91 pounds, you are 12 to 20 pounds under a normal weight for your height.   Some of your symptoms may be related to this fact.  Has anyone discussed this with you?