Can breast implants cause breast lumps?

[metalgirl70]

I have silicone gel breast implants.  In July I felt some pain in my breast and upon inspection, I found a hard, pea size shaped lump in the area of the pain. (about 5 o' clock)  In the time since July, I have had 1 mammogram and 2 ultrasounds, and neither one of those tests can see anything.  It's not a deep lesion, and I can easily feel it.

Currently I have  been seeing a breast specialist who has me come in every 3 months to an ultrasound, which never shows the lump in concern.  The surgeon can't feel the lump either, but I like I said it's easy to feel, for me anyway. I point out very clearly where the lump is, and I can easily feel it under my fingertips, yet I don't understand why the doctor can't feel it.

He says he's not concerned, and it's maybe scar tissue from the implant.  Can an implant make a perfectly hard, round lump in the breast?

This surgeon doesn't want to do any biopsy, due to the implants.  

I have seen two different doctors regarding this issue, and neither one seemed very concerned.   For my insurance, I need to have referrals before seeing a specialist, and my primary care doctor won't do anymore referrals for me on this issue since she doesn't feel like it's a problem.

I know it's probably something harmless, but what types of pea sized lumps can there be in the breast that never shows up on any imaging?

I have had pain in under my shoulder blades and in my spine for the last year, and again none of my doctors feel like it's anything to worry about either.  

My doctors probably think I am a hypochondriac, and maybe I am, but I just want someone to be able to give me some definitive answers.

I'm 38 years old, no family history of breast cancer.

Should I worry about this?