I Have Breathing Problem

I am a 20 year old male and for the last four or five days, I have been experiencing some difficutly breathing. It feels like there is a weight on my chest. It's like i'm breathing through a stuffy nose, even through my mouth. This feeling is releaved when I breath in the steam of a hot shower or boiling water. I also notice some releaf when I do some exercises, such as running in place. At times I notice my heart beating a little faster than normal whe I'm not doinf anything. I don't have any chronic pain. The last thig I remember doing before having this problem is eating quite a bit of peanut butter on bread. I remember having pretty bad chest pains while scarfing it down. I am think that it is an allergy of some kind that I never had before. I've never been diagnosed with asthma or anything, but I guess it could be. I do remember many years ago, as a young child, when my throat pretty much closed up. I could barely breath, my mom brought me to the bathroom and turned on the hot shower and I fell asleep and woke up fine the next morning. Could this instance be related ?