It sure seems as though everything is broken, but a quick peek at the Sox last 12 games--in which they are 3-9--shows the Sox have scored 2, 1, 5, 3, 6, 3, 0, 7, 1, 1, 1, and 2 runs. That's 30 runs and an average of 2.5 runs per game. So I really thing that's the biggest problem. Season to date, the Sox have scored on average 4.76 runs per game. From 4.76 to 2.5 is an awfully big dropoff.
In the same 12 games, opposing teams have scored 57 runs or 4.57 runs per game. Season to date, the Sox team era is 4.15 runs per game. So, at least for those last 12 games (3 wins, 9 losses), pitching is the lesser problem. And I think within the pitching the rotation has held up better than the bullpen.
The Sox still lead MLB in errors in unearned runs, but I honestly believe that 1) those 13 arms on the roster are the most important part of the defense; 2) even with the errors, the Sox hitting is far more important than the defense.