Your problem sounds digestive in nature. At least the acute one does. Wash that bottle!

Looking at the pic of your bike...

You may be approaching the point where the bars are too low for you to use the bar ends. Reference earlier comments about width and scrunched shoulders. Options are: cut your handlbar down. Raise the bar. Get a different kind of bar. Beware! There are very real mechanical issues involved in converting to a drop bar, and if you were going to do that, I would just buy a roadie.

I'm not a pro, but I don't like that forward saddle tilt. That will cause you to slide forward, placing pressure from the horn on your soft bits. The sliding forward will cause you to strain more with your arms trying to stay on the saddle, which could be amplifying the neck issues. As you prop on you arms, once fatigue sets in you lock your elbows and LEAN into your raised up scrunched shoulders.

Your saddle SHOULD be mostly level, with the aft end where your bum goes ever so slightly higher than the front in that level position. Some people place the aft level with the horn, giving it the appearance of an upward tilt. That kind of tilt will cause you to "fall" back on your saddle rather than forward, easing arm pressure, but impeding your ability to "crouch" without genital issues.

Check your saddle adjustment before moving your bars more. A forward falling moment on your saddle may actually be exacerbating this issue. If you find that leveling your saddle places you just a bit forward, then slide your saddle forward on the rails, moving you closer to the handlebars.