growth that is growing from underneath his nails

Question
I am not sure what is the cause for my guinea pigs strange growths underneath his nails are. The growths appear to harden skin with the structure of nails with have the characteristics of being soft, bendable, and yellow They only appear to be growing on his back foot and are different lengths. I need to know what the diagnosis and cause could be and if it could be possible that my guinea pig has started to grow a second pair of nails. He does not seem to be bothered or in pain from the growths so should they be removed?  

Answer
Hello Summer!
This is actually a rather amusing question for me as I was just going onto this site to look for more pending questions while my fiancee and I are taking care of our four guinea pigs spurs.
A spur, to make the last sentence understandable, is exactly what your guinea pig has. A spur is formed because there nail and foot health was bad as a pup. These small hard skin growths can be removed while trimming there nails with a simple nail clipper. They do not go away, and if left untrimmed they can cause a serious and life threatening illness called bumble foot (enlarging of the foot and paw pad).
So all in all your pig is not and will not be in any pain if you remove them weekly. You must do this for the rest of his/her life.