thanks for using health care magic.
There are several conditions that could cause the lump
you have for the past years. Skin tumour is definitely one
reason that cause a lump on the skin and has to be rule
out as soon as possible. It is also possible that what you
have is a kelloid that develope after skin lesion say cut or
etc and grew big to what it is now.
However, it is only after a physical examination and if
needed a biopsy
done that a right diagnosis will be made.
Concerning the pains in your testicle, you should consider
seeing a doctor but there is a chance that its just as a
result of pressure rather than an underlying pathology.
You do not need to be afraid to see a doctor because
unless you do so, you will never know exactly what is the
problem and you might not get cured or you might be wanting
to seek for treatment when its late.