I was diagnosis with mono on feb. 26th of this year. i still have pain in my neck where my initial symptoms arose. is this normal or should i go back to my dr?

Could be & Yes: Symptoms may linger for quite some time after mono. A follow up visit after a month seems appropriate. God luck!

Neck pain: It has only been a month so it could be residual pain from the swollen lymph nodes in the neck due to mono, but i would still go back in to the doctor to make sure it isn't something new or different.

Could Be Normal: Mononucleosis lasts a long time, and the swollen lymph glands of the cervical area many times stay sore and swollen for quite awhile. In my opinion, 30-days is not "long". That said, if you have other questions relating to your recovery, please be seen for a clinical follow-up examination by your pcp.