Can't Stay Hard Lying Down?

I have good boners standing up, but when I lie down I can’t maintain them.

I masturbate exclusively standing up, and have no issues with hardness when in a standing position. It points up at like a 45-60 degree angle.

But when I lie down it doesn’t stay hard unless it’s flat on my belly pointing at my bellybutton. The moment I point it up, it’s like gravity drains it.

Is this normal, should I be worried? I was thinking it might be due to pelvic floor muscle imbalance, due to my masturbation habits.

I am somewhat like that, and if I remember correctly, MakeHerGoCrazy also had that issue. I’m guessing it’s a back/glutes/pelvic floor issue.