| you will not loose any cut or mass from taking a day or two per week of rest. Quite the contrary, you will gain! Your muscle mass comes from rebuilding! Also, it is possible to have a fantastic body and a healthy back.
It is possible that you are focusing on your abs and not on your transverse abdominis and/or lower back. You must workout ALL core muscle and give them an even workout. Antagonist muscle weakness is a big reason for injury and pain.
Post your workout schedule and let us pick it apart some.
Don't be discouraged by taking a rest day, instead think of it as a healthy way to rejuvinate your body.
-Rip | 
