What It Is: Lady Gaga must REALLY be in pain, because she NEVER cancels shows – and she has done so now because she can’t walk.  She explained the situation on Twitter . . . saying, "I've been hiding a show injury and chronic pain for some time now, over the past month it has worsened. I've been praying it would heal."  She added, "I hid it from my staff, I didn't want to disappoint my amazing fans.  However after last night's performance I could not walk and still can't.  It'll hopefully heal as soon as possible, I hate this.  I hate this so much.  I love you and I'm sorry."  Apparently, she has severe joint inflammation.  She was supposed to perform tonight and tomorrow night in Chicago . . . Saturday in Detroit . . . and Sunday in Ontario, Canada.  Those shows have been canceled for now, but make-up dates will be announced soon.