For the last few weeks, I have had a weird feeling in my chest, almost like i am inhaling shorter breaths and exhale faster than normal. I also have a soreness mostly in the center of my chest, feels like a strained muscle or something, have a temperature every afternoon 99.5-100, and generally feel 'off balence' when i walk around. I had a chest xray that came back normal. Any idea what might be causing this?

Thanks