Aching pain at top of shin

Lately i've been experiencing constant aching pain in the tops of my shins, the pain is much worse on the outer edges and very very sore to touch. At first i thought it may have been shin splints but from what i've read that usually effects the inner edge or lower down the shin ?

I'm 21 and play football 3-4 times a week, once on grass and 2-3 times on astroturf, so far my life has been relatively injury free wondered if anyone could help me with this one ?

many thanks

Mark