Hi Ju, sounds like what I suffer from. When you are anxious or panicky your muscles contract, and you use more than you normally would. Imagine it like running a marathon, a couple of days later your legs ache like hell, it's the same with anxiety. I suffer from it all the time, it's my worst symptom. I went to the hospital and they prescribed me Kapake tablets which are for muscular skeletal problems, they are really good and give you a sleepy effect so I manage to get a few hours sleep. Kapake are only available on prescription so failing that anything with co-codamol in it.
Hope you find a solution soon.
Les