Paul Simon Cancels Two Shows Due to Chronic Injury

Paul Simon fans in Philadelphia are hearing the "Sound of Silence" instead of his voice this weekend ... because he's had to cancel two performances.

A post was shared to the singer-songwriter's Instagram Saturday ... letting fans know "chronic and intense back pain" required immediate attention -- and, he can't play his shows this weekend.

The statement explains the shows will have to be canceled for now ... because PS simply doesn't have the ability to reschedule them for a later date at this time.

Paul's going through minor surgery for the issue ... but, his next show is scheduled for July 7 in Long Beach -- though it's unclear if he will make that show either.

He's got more concerts set up for Los Angeles, San Francisco and Vancouver into early August ... so, he has quite a bit of time to recover before his tour comes to an end.