Pain In The Upper Rectos Adominis On The Left Side

pain in the upper rectos adominis on the left side when bending or crunching. I was lifting some large heavy boxes and it occurred after this. Could this be a tear? What treatment. Does not hurt when I breath deep or causing any sleeping issues. Notice it when I bed toward that side or straight down. If I put pressure on that area then the issue is less with bending.