Mark Ronson went from the DJ booth to a hospital bed ... and it sounds like he was trying to do way too much.

The producer/DJ just posted a photo of himself in the hospital, explaining how some heavy lifting during a DJ set resulted in him needing medical attention.

Mark says he was in the middle of a mix when he tried to turn the stage monitor towards the crowd to "give them some extra juice." Problem is, Mark says the stage monitor weighed way more than he thought and he ended up popping two tendons in his bicep.

MR sounds like he's blaming the production assistant at the venue ... he says the "house PA was so bad that I tried to one-hand turn the stage monitor."

Mark is hoping some laughter eases the pain, ending his post with some light-hearted humor, writing ... "Here we are, baby! #tornthisway"

Despite the painful muscle injury, Mark says he finished his set before seeking medical attention.

This is Hollywood after all ... and the show must go on!!!