I found a sore spot on my right breast and I am 18 i worry the worst.. what are other signs of cancer? I cannot feel a lump yet

It's hard not to worry when there's something not right with you isn't it?

Given your age and the fact that you are on Yaz, it's not unusual to have tender areas and even a some swelling on your breasts with your cycles.  Your breasts will continue to change for the next couple of years (even though you are 18) and with that will come some tenderness as well.

If the pain comes and goes with your period, it may just be hormonally related.

I am ssuming that you have to see a doctor to get the Yaz.  It might be a good idea for your doctor to check the area where you are having pain to see if there is anything there.

Having your doctor check it would help your worry too.

At 18, you should start doing self breast exams. Here's a link:(my "insert link" isn't working so you may need to cut and paste in your browser)

http://sisterearthorganics.wordpress.com/how-to-do-a-self-breast-exam/

so you can start if you haven't.  It's good to know your own body so you can make sure everything stays healthy.  :)

Savvy Sister is absolutely correct! It is easy not to feel alarmed when there is something different. Make sure you keep an eye on it and identify the changes with your monthly cycle.

When a woman performs self breast exams it is done to get to know their bodies on a regular basis so that abnormalities can be detected. A SBE is not done to "look for cancer" as much as it is done to know the normal patterns of your body.

If you do feel uneasy and are not comfortable with your pain, go visit your physician. It is always better to  have that peace of mind.