Undiagnosed Leg Pain - MRI

I have had a lump on my right thigh for over a month.  The past few weeks it has grown larger.  An ultrasound showed no signs of a blood clot.  An MRI showed no signs of either a mass in the skin, fatty tissue, muscle, or bone.  However, lump can be felt and pain persists.  Have not had any kind of injuries either from sports or heavy lifting, nor any kind of accidents.  Am a non-smoker, non-drinker, 5'7", 155lbs, with no other health issues.   What else can I look into in order to get to the bottom of this continuing pain in my leg?  What makes it worse is that the pain is only in my right thigh.  Your comments are appreciated..

[Demiguise]

Is it in your thigh skin to see or you just feel it? If hits
higher up near the joint-to-hip, it could be inflammed burser pad or the nerve ending from the lumbar/sacral region. I'm
guessing they did a lumbar MRI. Get your own copy to see if any
bulges or disk shift was reported. I have a calf pain that aches
once in awhile. Had MRI & was told it was do to multiple bulges
in spine. Sometimes the pinch-off skips the thigh area & aches at calf. It sounds something like a tendon inflammation. Tennis
Elbow will hurt but also form a swelling across forearm-pad &
hurts quite alot. Ice helps many things. Gd-luck.

[Demiguise]

Sorry, meant 92 before. I'd get a copy of the ultrasound for
sure. Sounds like it's fluid filled since it's getting larger.
May be a cyst? Whatever it is, ask Dr. if it's possible fluid
& can they do a small needle aspiration to explore contents.
Cysts don't always show up in mri's if radiologist isn't doing
a through job. They get eye fatigue & miss faint shadow. A solid
mass would pop out to them. Get copy of report for your 'home-
health-file'! Always sounds good.

[muffin1992]

Thanks for your comments, d-guise.  The lump itself can be seen as well as felt - the lump is located about 2-3 inches above the knee.   Every now and then I get a quick pain sensation just right at the lump - other times, it feels like it is pressing along a nerve - I cannot lift my leg.

[Demiguise]

Have you ever had any, even a slight knee injury? Maybe it
hurt & went away fast from just bumping it? Does it feel sorta'
rubbery? There is a condition that goes overlooked called a
'ganglionic cyst'. It's almost always in the wrist but has been
known to happen in knee near joint. It's a fluid that slowly
leaks to form a mass-like cyst. Generally no pain. I forgot I
slightly banged wrist into doorjam yrs. ago. 4 days later this
lump appeared & got bigger as weeks passed. Only hurt when I flexed wrist a certain way. Get copies of all reports.  I
think you may need an orthopedist to look at it. It's rare at
knee area & many docs just don't think of it.