Can you have radiation treatment while receiving chemotherapy?

Yes. Your radiation and medical oncologist should coordinate whether this should be done. Some cancers doing the treatment at the same time gives the best result while other cancer doing them in succession is best.
Yes. It depends on the cancer, but sometimes we give radiation therapy and chemotherapy together. It is much stronger that way but has more side effects.
Yes. In many cancers, outcomes are improved by having both treatments at the same time. Not all chemotherapies should be given at the same time as radiation treatment, but it would be unlikely that any physician would recommend an unsafe combination of chemotherapy and radiation.