I have that problem (aching for 3 days, Ibuprofen every 3-6 hrs to get me through it) with arms, legs and hips.
I finally quit doing all those sites, because I was simply not willing to hurt that much.
I inject only in my abdomen, and only 4x per week, because Shared Solutions does not recommend using sites more than once per week.
My MS Specialist is OK with that. (I actually made the change on my own, and told her about it several months later.) She says, "We do what we can."
In spite of my decreased injection fx, Copaxone seems to be working. I had a UTI in December, which usually triggers a flare. This time, it didn't!
Symptoms since 01/2002; Dx with MS: 10/2003; Back in limbo, then re-dx w/ MS: 07/2008
Betaseron 11/2003-08/2008; Copaxone 09/2008-present
Began receiving SSDI 11/2008