Forgive the length of my post. This is hard to explain....at least I haven't been able to make anyone understand so far!
I have issues with a muscle. I don't know what is wrong with it but it is doing some really weird painful things. Sort of along the lines of a massive cramp or "charlie horse" one might get in the calf muscle.
From my research trying to FIND what this muscle is called I "think" I have narrowed it down to the linea alba.
This muscle starts at the bottom of the breast bone and goes down to the pubic bone....it runs straight down the middle, between our rib cages. It is what connects some other ab muscles (rectus abdominis) or the two muscles that make up the "six-pack" ab muscles.
I was thinking "hernia" but I have always thought that hernias were a "tear" in the muscle. Could be wrong on that but I digress.
When I bend over to tie my shoes or to pick something up this muscle FLIPS over on itself. It becomes SEVERLY painful, meaning I gasp for breath.....it changes positions enough that it sticks out, creating an outward lump about the size of a walnut.....I can watch it FLIP back to the right position and then the severe intense pain is gone. Just like that. I can MAKE this muscle do it....have even shown my massage therapist. She freaked out.....It isn't something that I want to make happen of course but I felt desperate and countless times of trying to explain it wasn't getting through. I also have that terribly bad rib-cage pain and what seems like a thousand little marbles which are actually the knotted muscles that sit on them. The knots go in between my breasts and affect the start of my breast tissue. Anyhow, we are thinking that this is all just a part of the fibro and this muscle is just pretty well screwed.
When it does it's flip thing I have learned to arch my back as much as possible and start immediately rubbing the area with my fingers and dragging them in an outward motion towards my sides. Take a few deep breaths and watch it flip back into it's rightful position. It never happens without me engaging the muscle (bending over, holding in stomach, etc...).
It hasn't progressed in pain level ( I don't know how it could) but it has increased in frequency. I used to know that I would have 3-4 seconds of the bending over motion to get something done, feel it start it's "thing" and I could straighten up without it completing it's mission.....now if I even make an attempt to engage that muscle it starts the process. I have to do so many things differently now to try and keep this from happening.
Trying to strengthen the muscle would be impossible. Any attempt at a crunch is out of the question. Other things are starting to be affected.....forgive me but, these muscles are engaged during "relations" and DH is getting a little um, "stressed" with me. 
Any thoughts about this sounding like a hernia? It doesn't hurt when it is in place. No constant pain.
Thanks for reading!