TL/DR:  twinkle toes fell, boo boo on shoulder.  Much medicine man, no love.  14 months later shoulder pops.  Joy returns to OP.  Why?

In June of last year I had a little footwork mishap and fell.  Landed with my left arm extended, palm down and roughly ninety degrees out from my side

Hurt like a mofo and did not heal.  

During a doctor's visit for an unrelated issue several months later I whined to him about it.  By that time it was extremely painful to raise my arm, couldn't sleep in any position but on my back and was overall in constant pain and miserable.  Not discomfort but pain

He diagnosed frozen shoulder despite my explanation that I fell on it.  Gave me a cortisone shot, some exercises and sent me on my way.

Two months later I end up hospitalized, again for an unrelated issue.  I whine again when the nurses notice I'm not sleeping.  Different doc orders X-rays and concludes I have the typical 52 year old shoulder and wouldn't even do another cortisone shot let alone the MRI that I requested

So, the other night I had extended my arm out while seated, turned to reach for something behind me and something in my shoulder popped

Really loud

But I had immediate relief.  All pain gone.  Maybe a little discomfort but my shoulder has weakened over the last 14 months or so.

It seems to be getting better and my full range of motion is returning.

What the hell happened?

You dislodged the alien tracking pod.

MAGA!

Wish I had just dislocated mine. Yet I broke the Humerus in two spots and shattered the ball in the shoulder back in November. Now I have about 95% use out of it and really just need to work on the strength to get the rest back. Lots and lots of metal to rebuild it all. X-ray looks like a Shockwave.  Although after 3 months was back out shooting my AR and all my different handguns. I had a damn good ortho that was a combat medic and said he say shit over seas yet never saw anyone that fucked up their arm like I did. Hell he didn't even want to do the surgery to begin with yet he did and I give him praises every time I see him.

You probably had a flap of cartilage impeding your range of motion and how you turned it,flapped it back.

One of the ligaments was probably pushed into a bad position during your fall. Extending your arm popped it out.

Torn meniscus with a flap of cartilage folded over on itself and you moved just right to allow it to lay down flat.

ETA: Shit, beat by two posts and stupid to know it....lol.

Can it really be that simple let alone have stayed that way for over 2 years?  Probably 10 doctor appointments and 3 hospitalizations of 7 days or longer with multiple exams and X-rays?  And not one doc could see it?

Boggles my mind but so far I'm happy it's getting better

this right here.

first post overtime, aliens?

Endometriosis.

When you moved it the other night, it scraped off some of the endometrial tissue.

Ask your doctor about taking hormonal suppressive therapy for it.

Now that you mention it I've noticed my cycles have been a little wonky lately

Maybe I'll scrape a sample off my taint and have it analyzed just to be safe

Go ahead and IM me your address and I'll send the specimen.

You still accept Medicareaidobamafsa?

On a serious note, it could be several things.  Maybe a small piece of calcified tissue that literally popped back into place.  At this point, I would not do anything about it such as any imaging.

Yeah, I'm leaving it alone.  It's still tender but feeling better every day.  I've had restricted range of motion for over 14 months.  Gonna take some time but it will strengthen back up.

When it popped my son, who was sitting about 12 feet away playing a video game while wearing earbuds, looked up and said "did you hear that?  Something hit the house!"

I have had a similar issues.

Way back in the day, I was playing basketball and took a spill landing on my elbow. I had extreme pain when I attempted to bend my forearm, so I went to the doctor. The doctors found no fractures or anything else that would cause the pain. Due to the pain, I kept shopping for a doctor who could diagnose my problem. I finally found a doctor who said I had damaged my ulnary nerve and needed surgery. As soon as she left the room to retrieve the paperwork, I began bending my arm back and forth, going from straight to extreme pain. On the last bend, it pops and a wave of relief come shooting down my arm. The doctor comes in a couple minutes later with the paper work. As she sits down, I stand up and tell her I will not be needing the surgery. The cut happy doctor proceeds to tell me surgery is still needed. I thanked her and walked out. My arm will hurt from time to time, but I can pop it to relive the pain.

Then I thought I tore my rotator cuff lifting and carrying a very large log through the woods. I had constant pain for years, but I learned to deal with it. Then one day I go to put my seatbelt on when my shoulder popped. Instant relief. Again, the pain will return, but I simulate grabbing for a seat belt and it will pop.

yep. Won't show up on imaging unless you have an MRI.

Ps, just getting over major shoulder surgery. Don't do it unless you HAVE to.