It's normal. The better shape you are in the more likely you are to have a higher libido.
I would say you are pretty normal, dont need to tell you what you need to do when you get an erection, I have had to do it in the privacy of a shower cubical several times, I am not gay either, wouldnt make any difference if I was, amazing what the body does when you work out.
I think this might be normal, I am a trans masc (still a bit dyphoric) but the same happens to me. Every time after a 30 min workout with my siblings, I go to the bathroom to take my shirt off for a bit, but then I feel like I've been turned on. No I am not from Alabama nor turned on by my own siblings. I just feel horny, idk why.
Yeah. Possibly, it is due to the relase of endorphins which your workout caused. As crazywillie sez, amazing what the body does when you work out. After I go for my jog and take a shower, I get an erection sometimes. I can usually control it. But maybe it's from being in a strange place that you have a hard time controlling it. I find, with the penis, it's often a matter of reverse-psychology. When you don't want an erection, it comes up and stares you in the face, when you want one, you can't get it - sometimes. :(