Radiotherapy can cause general side effects such as feeling sick (nausea) and tiredness (fatigue), but it’s also likely to make the inside of your oesophagus inflamed, causing short-term soreness when you swallow. These side effects can be mild or more troublesome, depending on the strength of the radiotherapy dose and the length of your treatment.
It's not unusual to feel worse before you start to feel better. Some people can find this a very difficult time and they may feel low or even depressed for a while. The clinical oncologist can advise you about what to expect.