I've never been able to do the back bend thing and bar two inner strings. If the first position A is an absolute necessity, then I try to get one finger planted early and then wedge the other two in carefully, usually (*oIMRo) or (*oMIRo). There are a some classical pieces that call for a half bar on the EAD, which involves the bend-back trick.

Maybe that joint got sprained ... bummer ... I usually just bend enough to mute the treble E string, rarely enough to play it.

~S~