Strange symptom

I was diagnosed with seminoma in January 2004. From then I received 4 cycles of BEP, and after recurrence in mediastinum - 4 cycles of BEP and radiation to my abdomen and chest. Shortly after chemotherapy in 2004 I developed peripheral neuropathy which subsided after a few months. Similarily, after radiation I had L'Hermitte symptom for 2 or 3 months. Since the completion of treatment I have had also prostatitis which seems to be healed at the moment. Sometimes I am tired at the end of the day and I have tender points in my body occassionally. Three days ago I felt some prickling(tingling?) in my both feet as if something was crawling in bottoms of my feet. When I go to bed and wake up in the morning, I have no sensation of tingling. As the day goes on, this tingling comes back and it is sensed during sitting or standing. It seems to go off during fast walking. It is not intense but it occupies my mind. I have also some tender points in my blades, near my knees and in my buttocks. I started to take Lecithin to supply some B vitamines. I wonder what is going on with this crawling feeling? Is it fibromyalgia, some deficiencies of minerals, MS or peripheral neuropathy? I chew gum every day, about one pack daily in average therefore I wonder whether there is any relation to aspartame.