I am 62,(very healthy) 9 days ago I was sitting on the floor for about 2 hours sorting out papers. The next day I got up and had an aching in my right thigh. it got worse during the day .. The next morning I woke up in agony and had to call a friend to be on standby to take me to the ER the pain was so severe. I ended up getting an appointment with my Dr who did an ultrasound to R/O a clot. He has referred me to a Neurologist this friday.
Back up...A little history... I do get a pain in my hip/groin after riding in the car for more than 2 hours (this has been happening for years) it goes away when I get out and stretch and did not happen again until another long ride.
other facts, I did have endometriosis(scars?) 30 years ago.

back to now... I am in pain constantly, when sitting(anywhere, toilet, table,car etc) when I get out of bed the pain is unbearable for at least 30 minutes until the Vicoden kicks in and the (nerve is stretched?) the only time the pain subsides is when standing and or lying flat . and actually I was awakened by the pain in the middle of last night (first time pain came while lying down.) The pain is in my Hip, groin, buttocks and radiates down the front of my shin.

So , I am looking forward to my appointment... but , after googling alot of my symptoms I ended up with this possible problem.... What do you all think?
Thanks for listening.... any thoughts would sure be helpful.

Welcome to NeuroTalk:

As far as I understand it, MP involves only the lateral femoral sensory nerve. It does not go down to the shin, and does not
hurt in the buttocks. (It travels in the abdomen).

However, the sciatic nerve and other nerves do go down the buttocks. There is a condition where compression in the muscles of the buttocks...can happen...This is piriformis syndrome.

Here is a medical site for doctors that explains hip pain in general. It has a portion devoted to MP.

Figure 2A shows the sciatic nerve coming out into the buttocks on its way down the back of the leg.

Figure 2B shows the lateral femoral nerve exiting the abdomen to the front and lateral thigh.
http://www.aafp.org/afp/2000/0401/p2109.html

This link explains piriformis syndrome:
http://en.wikipedia.org/wiki/Piriformis_syndrome

Sitting on a hard floor for a long time, could compress this nerve (sciatic) where it exits the buttocks.

Thanks MrsD, I checked the link you provided and also googled for more info and diagrams of the nerves involved. I think I may have mis led when I stated buttocks as those diagrams for Piriformis syndrome are in the buttocks back area when my pain is more on the side (hip area ) and I do not have any pain in the back of my leg at all. My pain is mostly outer thigh, outer knee area that sometimes radiates down the outer shin area, and sometime around the front of the thigh to the groin area. I have no back pain at all .

My MP is only on the front of the thigh. I developed mine from
abdominal surgery.

People can develop MP from too tight compressive clothing...like tight belts, and jeans. Also it can come from compression along the spine (with or without back pain), as that is where the nerve comes from before entering the abdomen.

Also people who donate bone marrow, get needled in the back of the hip to reach the bone marrow in the pelvic bones. This procedure can also cause MP.

People vary in anatomical distribution of this nerve, at either L4 or L5. So surgical interventions may damage it or other types of medically invasive procedures.

Males can develop it on the side of the trousers where they carry their wallets.

There are many factors that can cause MP.

I used Lidoderm patches very successfully to block this severe pain, and never took narcotics or other drugs.
I applied them to where the nerve exits the abdomen under that ligament as illustrated in the link I gave you. After 2 weeks of every day use, the nerve went to sleep. So I have a remission now.

Police Officers get MP from constantly Sitting with a thick belt on. Nerve Irritation of the Nerve could have happened to you easily from sitting on the floor, it would go away in a few days just as well. MP for me went from the top of my though to outer side. Another condition that can give the same symptoms is Bursitis in the Hip joint, and would hurt much more than MP. It sounds like you are describing. MP is light touch only, Bursitis of the Hip hurts like Hell right away!!!! that other thing described.. had that, could easily be that too.