Front Brakes

Hi==Have a small problem== Front brake is not releasing==Thought I was losing power and pulled off pavement into my front yard==Wheel was turned and stopped spinning immediately when it hit grass, slapped me on the ground like a hamburger patty==dislocated shoulder, bent handle bars & fork==couldn't believe it (2 weeks ago)==Today I took off the front caliper in anticipation of receiving one that I found on eBay this week===BUT much to my amazement, the cylinder in the caliper works freely and easily==Is there a check valve in the master cylinder that could be faulty and keeping pressure on the caliper? Or the junction block under the fork, does it have a check valve in it that could be faulty?? Any help appreciated==Don't want this little scenario to repeat==Chris