Sorry to hear about your pain. I'm a beginner and even the slightest shin encounter hurts, so I can feel your pain. With that said, you should be blocking with your knee, not your shin. The term 'shin block' is a misnomer, we only use our shins in practice. The Thai words translated to knee block. Think about it, if a guy throws a kick and hits your knee with his shin or foot, who is going to feel it more!