Is it normal that i can't get horny without pain?

I don't know what it is, but recently (for the past 8 months) I haven't been able to "rock steady" without being in some form of pain.

Sometimes, I will even go on the internet ahead of the time that I am going to be with a date to look up movies where men submit to women, so that I am more aroused later in the evening. I feel this to be semi-normal, however ... recently, I have found that I really like to see guys fighting each other is super un-straight ways.

Is it normal for a straight guy to like to see two guys doing stuff to each other? If I feel extremely apprehensive to other homosexual tendencies, then is it still possible for me to be gay, because I like to see guys grab each other? Should I try to experience something out of my norm to find out?