Oone-sided nursing strike?

I am at a loss what is going on. Our baby boy was always a great nurser. He has upped his intake of solids significantly over the last weeks, he is now 10.5 months, but he still likes to nurse - wake-up, midmorning, nap-time, bedtime, and a lot (really a lot) during the night.
 
For two days now he has refused the left breast always asking to switch sides or latching and either biting or pulling away immediately (and hurting me). I have to hand-express or pump that side but it does not work well, I can't get a proper let-down, so I am engorged and in quite a bit of pain. I am also afraid of losing my supply on the left side. He nurses well on the right side.
 
Any ideas what might be going on and what I could do?

 

Ouch, that must hurt.

How about a different position on that side than how you usually nurse? Perhaps he is uncomfortable on that side for whatever reason?

 

Update:
I got him to nurse the left side properly by latching him while he was fast asleep. I know - he is nearly 11 months and nursing too much at night anyway, but I was in such pain ....
This morning I saw that he finally cut 2 of the 3 teeth I could see coming through and that seems to have been at least part of the reason because I can now offer both sides again; he prefered the right but took the left side ok-ish today.

 

Poor kid! I'm glad you were able to get him to nurse and relieve that pressure.