Awww Kittygrrll, I understand the worry as well. I'm going through something similar. One breast is very tender/sore in just one spot, although there are no lumps. However, as my period gets closer, both breasts get lumpier. My family doctor said that pain is not a hallmark symptom of breast cancer, but sent me for a diagnostic mammo/ultrasound just to be sure. That was my first experience with a mammogram, and I was scared to death--not of the test but of what they would find! It turned out just fine as the radiologist and sonographer couldn't find a thing.
I have an appointment with my obgyn in a week, so I'll ask about it then. I'm guessing it's just a hormone thing, but still scary.
My philosophy is: If my hubby is getting fed up with my worries over something, then it's time to see a doctor :)
How many months has this been going on for you? I'd say if it's been two and you notice a pattern, it's probably fine--but best to check with your doctor. Easier said than done, I know, but as my mom pointed out to me-if there WAS something sinister there, avoiding the doctor isn't going to make it go away :)