I am 42 years old and my mother had breast cancer, so I naturally get concerned when I see changes in my own breasts. I faithfully have yearly breast exams with my GYN as well as an annual mammogram. I admit to not being so good about my self-exams

. About 5 weeks ago, my husband noticed a red spot on the upper (outer) left side of my left breast - he at first thought it was a pimple. I didn't look like a pimple to me, but I was busy and just didn't pay much attention to it. I looked at it later and realized it felt raised on the skin and when I pushed harder on it, I noticed that it felt hard underneath, but not real deep (if that makes any sense). I decided it was probably just a skin irritation and left it alone. The color seems to change from time to time - sometimes it's darker red and other times it's lighter red and there seems to be what I can only describe as a shadow around it. When I pull the skin taught around it I can actually see the "lump" which is quite irregular in shape - it's very small though - maybe only .75cm.
I have noticed that my left breast seems to be a little bigger than my right and when I put my bra on this morning I really noticed that the left side did not fit as well as the right. It seems to be bigger around the outside. Isn't it normal for one breast to be larger than the other anyway?
I have an appointment later this week with my GYN to have this looked at, but I've been curious to know if anyone else has ever experienced anything like this. I know breast cancer shows up in different forms for everyone and since this doesn't fit the "feels like a marble, or a pea, or a grape" symptom I thought I'd see is familiar with anything like this.
I'm not easily scared - I'm very realistic, so if anyone has been diagnosed with breast cancer by something that started out like what I've described, please don't be afraid to share it with me.
I'm grateful for any comments!