Lump on left testicle feels attached possibly or maybe the vein that runs along side lump is on back side of ball?

See a doctor: Might just be a varicocele but any lump in the testicle should be checked by a physician.

Get checked: Any lumps palpable on the testicle need to be evaluated to get properly diagnosed.

On the Internet: Given your age and your description you need an examination. Your family doctor will be very familiar with this and be able to help you deal with this common problem.