I have a painful feeling in my hand between my fingers when i surf. the water is no cold, something about 20c. it's normal?

You could be having: A circulatory problem, where exposure to cold results in pain, numbness/tingling/cold feeling in fingers/hand. Bluish tinge is seen commonly. This is the raynaud's phenomenon. Other rarer causes might cause it as well. See your gp or a hand surgeon, for starters, but might need a vascular surgeon as well. It could be normal, but have it checked out first, to ensure its not something else.