Yes get another opinion. Even if he thinks it is nothing a year is to long to wait. Most doctors recommend waiting 3/4 months. My OBGYN and my PCP told me my pea size lump was nothing. I insisted on a mamo and ultrasound and it was cancer. It may be nothing but put your mind at rest and get the 2nd. I wish you well.
Yes, I would go for a second opinion to a breast specialist. In Los Angeles, there is the UCLA Breast Center that would see you. If you are close call them or ask your ob/gyn for a referral. A mammogram, ultrasound or MRI should be done, I would think. Dont wait. I found a lump in December and now I know to go directly to the best breast specialist you can find.