Gynecomastia or breast cancer, advice?

[enixn]

Howdy.   A little intro, I'm 22 years old, male, and in somewhat good shape (a little overweight.)  I've had very slight pain in my left breast on and off for a couple of years, lets say a maximum of 2.  It's never really bothered me too much, other than the occasional slight throb, or mellow pain, not sharp really.  I guess you could say I've noticed the hardness near the nipple top right of my left nipple (if you were facing me looking at it) increase.  My right nipple has something similar, but has hardly ever had any pain associated with it.

When I say the pain was intermittent, I'd say I might have noticed it a couple days out of the month or maybe only once a month or every other month up until just recently. 

I started smoking cigarettes back in august and had been smoking marijuana for about 2 years now.  I just quit both, cold turkey, on jan 1st as my new years resolution.  This last week has been hell for me, and still is, as I've been experiencing some troubling things with my body.  First thing I noticed was a tightness in my chest that seemed pretty intermittent, but would last a while, especially at night, contributing to my past 3-4 day insomnia.

Coupled with this is the pain in my left breast, which has increased to pretty much daily, almost sharp pains.  The pain was at first associated with just the hard outside rim, but felt like it was throbbing deeper as well.  Each day seemed to be getting worse, so I ended up going to see a doctor yesterday. 

I explained all of what I just explained here, and he then proceeded to examine my nipples.  He felt mostly just around the nipple, and found what I was talking about at the border of the areola.  Feeling the other side he indicated he found it on my right breast as well in the same place and just about the same size.  He basically told me that this was actually a common thing, to not worry, and that if it persists in about a month to go get an ultrasound.

The day after (today) I noticed that the pain has spread to include a small area between my breast and armpit on 2 little "bumps" under the skin, which are also mildly painful when I press on them.  I also just had diahrrea today for the first time in a while (months-since last I was sick with a virus). 

It is winter time here, and I usually get sick during the winter times, but all these symptoms are leaving me confused as to what could actually be causing everything.

As of right now I'm feeling a little nauseous, have a slight headache, my left breast just feels slightly "sore" but doesn't really hurt when I press on it.  I've never had any fluid come out of the nipple.  If I flex my pectoral muscle and feel about halfway between the breast and armpit on the outer-ish side, I can feel 2 of the little bumps that are normally present bordering the muscle a little enlargened and sore.  I'm about to sign up for some insurance and go get it ultrasounded because the first doctor's prognosis seemed a little offhanded. 

It is winter time here, and I've read that swelling of lymph nodes and irritation of gynecomastia can be attributed to infections as well, Which I feel may have been exacerbated by my quitting of both smokings, evidenced by my recent diahrrea and general feeling of not-wellbeing...but my mind is still ill at ease.

Any advice or input is greatly appreciated. 

Thanks.