I Have Numbness And Tingling In My Left Arm, It

I have numbness and tingling in my left arm, it starts at the shoulder and goes down to my thumb and forefinger, thumb is the worse. No pain really. I can hold my forearm up like a reversed L and it subsides. I did have a stiff neck a few weeks ago, also had numbness and tingling which affected my whole hand, had Chiro tx and the neck is better and the numbness and tingling is now concentrated just in my left thumb with just a bit in the forefinger. Thought maybe pinched nerve in shoulder joint or elbow.