Hernia or Undescended Testicle?

Firstly, I'm 16 years old.
Now, I have a lump in my groin area, it's about an inch above the top of my penis, and towards the right hand side. It visibly protrudes outwards, although not by a huge amount.
I've been aware of the lump for a while, but it didn't bother me all that much as it didn't cause much discomfort. However, recently I've been doing a lot exercising to get fit for the new football season, such as light weights, running, press ups, sit ups etc, and this morning when I'd finished sit ups it became fairly painful in this area for a period of time.

I've done research on the Internet, and the lump seems similar to a small inguinal hernia, which is seems fairly possible seen as though it become uncomfortable with exercise, which I believe is a symptom of a hernia. When I stand straight and press onto the lump and cough, it also seems to protrude more.

However, I have only one testicle in my scrotum, so I'm not sure if what I'm experiencing is caused by an undescended testicle, or a hernia.

I've heard that there is sometimes a visible lump when a testicle doesn't descend, although I'm not sure if this is always the case. I've also never heard of anyone experiencing pain in an undescended testicle, which is why I'm unsure about what this is.

Obviously I will be taking a visit to my local doctor to have this checked out, however I'd like to have more of an idea of what it possibly is before I give my suspicions to the doctor.