I had the same thing, I had to wait a week for a doctors appointment. worst week of my life, i thought i had freaken testicular cancer. The doctor told me that while doing squats, you can sometimes pull a muscle around that area and the pain can appear to be in the testicles but is really more of a pulled groin. but i had pulled my groin in football, and i could barely lift my leg, and this pain was just an aching feeling in one of my balls. yea it took a week or two and i didnt lift legs, and the pain went away.