Hi Molly, welcome and thanks for your question.  Arthralgia (joint pain), leg cramps, and pain are listed under the skeletal side effects.  I took Forteo and didn't have this problem, but since we all react differently to this its hard to say how anyone will react.  Do you have any arthritis that could cause this?  Most people have some form of arthritis, but if this only happened after starting Forteo it's hard to say what might be causing it.  It could be the drug or maybe something else.  Talk to your Dr about it and see if he or she can help with the pain.  Hopefully it goes away soon.  Here's a link that lists the side effects of Forteo from Eli Lily, it starts on page 4.

Good luck...