Better shoulder work options?

[hokypoky]

Twice in the last month I've pulled something below my neck, that spot down next to the shoulder blade, which turns into a really stiff, uncomfortable pain all across my shoulders. I caught my form doing military presses in Boot Camp this week, and found it hard to keep my neck from tensing up. I struggle a little getting the barbell over my head for squats, so I really would like to work on my shoulders.

What exercises could I do for my shoulders? (I also have to really watch my form on those lying bent arms pullovers in GS BSB.) I do belong to a gym, but haven't tried any of the machines there. I don't know if a machine would help me with form. Any ideas for this girl with wimpy shoulders? x(

Thanks in advance ...