Question: Electric type shock in buttocks, rectum down leg, doctor don’t know cause

I’m seeking advice, any help will be highly appreciated.
Background: Last year I felt a slight throbbing in rectal area which eventually subsided.
5-6 months ago the rectal throbbing had come back. Its quite difficult to describe, at any given time, 24/7 including now as I write, I can feel my heart beat in my anus as well as my buttocks. Its so strong It could shake my body down below when Im laying down. Occasionally, perhaps once an hour, maybe less, ill get a quick twitch or electric type feeling in my buttocks, it could be in my butt cheek, or in the rectum itself in the form of a shooting pain. This lasts maybe a second or two.
More recently, I feel like the aching thats occurring down below has radiated down my leg, i feel like the back of my leg aches as a result of this.
Other things to note since ive been experiencing this: increased gas, foul smelling gas, more frequent bowl movement, slightly thinner stools occasionally. No bleeding. No tar like stools or blood noted.
Combined with all this, I have chest pains, particularly around the sternum however I get these shooting pains that feel like a needle being pressed against my skin for a quick second from under my skin. These could happen anywhere on the upper torso. In the last two weeks, i feel like i have the need to cough, and I do, even though im not sick. And when I do cough it feels like there was no reason to. If i take an extremely deep breath, It hurts on the left side of my chest and it feels like the lungs.
Sometimes when im out and about during my daily activity, i feel slightly dazed or dizzy or lightheaded, not sure how to explain the feeling.
Ive been to the hospital numerous times, albeit I am in Canada with awful healthcare, they’ve done a cardiogram on me, blood work and a rectal screening. You’d figure they would have done more. They’ve ruled out the possibility of hemorrhoids and prostatis based on the rectal screening
I need advise, I don’t know whats going on with me, something isnt right. The throbbing in my Anus and buttocks is still going on after all this.
Thanks