Pain when crossing left leg -- Piriformis syndrome or something else?

I started gym training 3 months back. May be the trainer pushed me hard with leg press or squats, I noticed limited mobility of my left leg after few days. I notice limited range of motion of my left leg when I do any of the following: 

* I try to put my left leg on top of right leg, 

* I try to do breast stroke in swimming to push my left leg out, 

* Anything where I need to rotate the hip externally or internally. Even getting out of car causes sensitivity in leg,

It's too sore to perform full range of motion with left leg. I get pain in upper thigh muscles  and pressure extending towards hip that limits range of motion. 

In addition, I get pain in upper quadricep muscle (probably rector femoris) of left leg when I lie down and bring my left leg and knee towards my right shoulder, OR, if I do child sitting posture in Yoga 

I have seen 4 doctors in past 3 months but no avail. The latest I am seeing doctor feels it is Piriformis syndrome which causes pressure on Sciatica nerve when Piriformis muscle is compressed. I am not sure if it is the correct diagnosis. 

I did an X-ray of hip & back and they are all normal. MRI of lumbar spine is also perfectly fine with no evidence of herniated disk.

Moderator comment: I have removed the link(s) directing to site(s) unsuitable for inclusion in the forums. If users want this information please use the Private Message service to request the details.

You need to see an orthopedic doctor. and that’s sciatica pAin. It could be for a herniated disk . That happened to me.

Thanks for the response. I already consulted multiple doctors and got lumbar spine MRI, which shows disk is fine and nothing wrong (except  two notes - "mild facetal arthropathy" & "loss of lumbar lordosis suggestive of paraspinal muscle spasm&quotwink