Yes, rad is radiation. Where were you radiated? Everybody reacts differently to it and it may not be so bad in most parts of the body but in the head and neck area it's absolutely terrible. 2nd and 3rd degree burns in the throat, mucositis (it's much worse than it sounds), constant pain, the inability to swallow even saliva, damage to the mouth and gums (blisters, thrush), permanent damage to salivary glands (saliva is a very underrated fluid, you don't know how much you need it until you lose it), etc... Many people (myself included) lose the ability to swallow and have to relearn it. Thankfully most ill effects are temporary and the permanent ones can be dealt with.
I hope I didn't scare any newbies. It's always good to hear someone who goes through it easily. It gives the newly diagnosed some hope that it won't be so terrible for them.
Good luck.
Joe