Ok... IF you meant that the single event of flipping heads the 11th time in a row independent of the other outcomes then .5 is my answer.
Having already flipped 10 straight heads the probability of flipping another heads would be 1/2048
The probability of flipping 11 consecutive heads is 1/3.602879701896397e+16
The probability of you getting head is about.... eh.. nevermind..