Throat Choked Feeling

You know that throat choked sensation you get in Standing Seperate Leg Forehead to Knee(Dandayamana-Bibhaktapada-Janushiransana) pose?  That feeling that makes you feel like you can't breathe?  That sensation that there is something wrapped tightly around your neck ready to choke every bit of life out of you?  Ok, maybe you don't.  But this is how I feel in this pose. 

I've had an issue with my neck and my throat for as long as I can remember.  I fall asleep with a hand up by my neck, just in case some psychopathic killer sneaks into my house in the middle of the night and tries to choke me.  I cannot fall asleep wearing necklaces.  Turtleneck sweaters freak me out and make me feel as though I'm going to suffocate.  Too much neck nuzzling makes me jumpy and ticklish.

When I first started practicing Iyengar yoga, 3 years ago, Savasana was the most difficult pose for me.  Lying still at the end of class for 5 minutes was nearly impossible.  I always felt as though some unseen force was pressing down on my throat.  It would get heavier and heavier until I would have to reach up with my hand and rub my throat.  One day I pushed through the feeling.  I lay there and concentrated on my breath and allowed the weight to come across my neck and just as I thought I was going to be suffacated by this unseen force, it melted off my skin like warm wax.  And from that point I rarely felt uncomfortable or panic when I lay in Savasana or went to sleep at night.

Until this week.

Suddenly, my favourite pose, Savasana, has become hell.  That feeling of creeping weight is back.  I stare at the ceiling and try to focus only on my breath.  It doesn't work.  I reach up and cup my hand around my neck just to make sure there is nothing there.

What the hell is this????

Does it have something to do with my throat chakra?  Some kind of connection with my growth in expressing myself since I've started Bikram yoga?  Is it to do with my thyroid gland and the fact that my metabolism and hormones are becoming more regular?  Is this the same kind of reaction that I go through with, for example, the Spine Strengthening Series?  Where for periods I love the poses, I am strong and willing and able and then this switches and I am in hate with every pose and I struggle both mentally and physically?

I really have no idea and am at a bit of a loss for why I have this affliction with my throat and my neck.  But as most of the yoga instructors say, "If you are struggling, that's a good thing!  It means your body is changing." So I'll take this in stride.  But if anyone has ever experienced this or has any opinion on why this would be happening, please share!