Okay, I apologise for expecting everyone to read an essay before

I hope this concise version will attract some responses
Does anyone think I have a chest infection or could these symptoms be indicative of something else?
* I am constantly aware of a tightness - or even a sensation of pressure - within my chest in the centre just below my throat and sometimes in my throat;
* the tightness makes exertion extremely frustrating (pain isn't exactly the word) and if I do try to exercise I have to stop regularly to take big breaths;
* I am NOT finding any relief from my salbutamol inhaler anymore (I've had my administration technique approved by a nurse);
* I DON'T have a cough;
* I DON'T have any typical hay fever symptoms (such as watery eyes and itching) other than breathlessness.
I am still waiting for the results of my chest x-ray and now some blood tests but I am worried that neither of these will present any signs of a problem because the doctor seems to think there's nothing wrong with me.
Does anyone think I may have a sporting injury? Around the time of this breathlessness first presenting itself I started a new weight lifting regime which put considerable pressure on my chest. Is it possible to cause long-term problems this way? Thanks for reading