What Are The Side Effects Of Depo Provera Injection?

I'm currently on the depo provera shot q 10 weeks. When I had the shot Dec. 8th I ended up in the hospital because I had horrible headaches and they said the deep muscles in my neck being tight and were pulling on my scalp. My last shot was on Feb. 16 and I was back in the hospital because of bad lower back pain and they said it was because of deep muscles in my back being tight and pulling on my spine. Could the shot be causing the muscles to tighten like that?