is it allergies??

hi everyone,
okay I am 16 years old and am trying to solve some problems I've had forever! I was just hoping to clarify a few things before I visited a doctor

okay, here goes...
I have had a chronic stuffy nose for a very long time, and it lasts all year, which is why I never assumed it was allergies, since i thought allergies were seasonal. My stuffy nose always seems the worst when I just wake up, or when I get home from walking from the bus stop. It isn't totally blocked up, most of the time, and I can usually still breathe through my nose. I sneeze alot (three, four, five times in a row) but never right when I walk outside or at a time that would clearly state I was allergic, like when the cat comes close...
I get really itchy eyes (this one seems to be seasonal) but I don't know if it is allergies, because I do wear contacts, though they've never bothered me before. My nose is also itchy...

Also, but whether this is unrelated or not, I don't know, I get headaches. I tend to get them alot, multiple times a week, and a friend mentioned that it might be due to allergies. Can allergies cause headaches?

Another problem I have is that I clear my throat alot. I think I usually feel like I have to clear my throat when I finish eating, but it isn't restricted to that...and that doesn't seem to make sense? I also get an annoying cough everytime I laugh hard (which is ALOT!!) or when I stop running. But I didn't think it could be asthma, because I had asthma when I was very young and had grown out of it...but it couldn't come back, could it?

If anyone can help, it'd be awesome!
thanks

Get a doctor to check you out - if your nose is always blocked you may have some sort of sinus problem