A recently-released voicemail from an emotional Conrad Murray reveals Michael Jackson's disgraced doctor is suffering from insomnia and a shoulder injury as he serves out his involuntary manslaughter conviction.

Murray has been held at the Los Angeles County jail since November, 2011, when he was found guilty of administering the fatal dose of anaesthetic propofol, which claimed the King of Pop's life in 2009.

The physician was moved to a larger jail cell last year after his legal team went public with concerns he was facing permanent health problems due to his cramped living quarters, but in October he was hospitalised for pain in his right shoulder and marked venous stasis of his lower extremities.

And now it appears things have gotten so bad, he can no longer sleep.

TMZ has obtained a voice message that Murray left for an unidentified pal, and in the clip he can be heard crying uncontrollably and pleading for help from Sheriff Lee Baca, who has the ability to release the 59 year old into home confinement for the remainder of his jail term.

He says, "I need help... I've been calling everybody I know to answer. Nobody has picked up. My right shoulder pain has (gotten) so bad I've been in tears since about 2:30 in the morning. I can't use my hands anymore. I have no more use of my arms... I can't sleep now. It's very hard and I'm in constant pain."

He adds, "For eight months I've been in this pain, with more and more loss of my limbs... I've been using Motrin that they've given me to take the pain away... They've tried to make it better, as I have requested by now (hand)cuffing me in the front rather than behind. But the injury has not been addressed and I think I have a right to complain if I'm in pain..."

"All I'm asking for is can somebody please help me? Please... I try to call my attorney, she can't even pick up the phone. Can you do me a favour, maybe call the sheriff himself, call Sheriff Baca. Ask him to please see me, maybe he doesn't know what happens in here... I'm just asking for some help, that's all I need. Nothing more."