So I went to the gym today, I got on the bench and did 10 sets of 10 reps, using medium weight, took about 30 minutes to complete, only thing I did other than biking and a few chin ups, and now my shoulder feels a little sore? Does anyone know why?
It's likely all the bench-pressing that you're doing.
Too much volume: 10x10 is a very high-volume program. Most lifters stick to around 3x10 or 4x8 for hypertrophy.
It also might be a muscle imbalance. Your pectorals are stronger than your back-muscles, and it's screwing with the (very complicated) structures in your shoulders. Take a break from benching for a few weeks and do some more rows/pulldowns/chin-ups/face-pulls.