Lumps on Penis Head

Hi. I have some white lumps attached to the head of my penis, underneath the foreskin. My foreskin doesn't retract (and never has) so it's difficult for me to see exactly what they look like - but they're clearly visible when erect and can be felt through the skin also. I first noticed something 2-3 years ago, but didn't do anything because they didn't cause any pain. They are now more numerous and the head is sometimes slighty sore, but still don't cause any real pain. My doctor says it could be a build up of smegma and has asked me to consider circumcision. However, whilst there may be a build up of smegma as well, I don't think this is the only diagnosis; the lumps are firmly attached to the head of the penis (not just round the edges). I want to avoid circumcision if at all possible, particularly if it wont solve the problem because there is something other than smegma there. Any ideas please?