Hard stools irritation burning sensation

I have always had irregular bowel movements & oflate the stools are hard. For the past 10 days, there is an irritation in the anus when passing stools, sometimes painful. Last night again the stools were hard and passing them, there was burning sensation and dull pain which lasted the whole night. I feel as if there is some wound inside the anus though I cant feel it by touching. I have been eating only fruits for dinner for the past week and plan to continue always. today I ate fruits through the day hoping to have soft stools, in the evening I passed slightly softer stools with little discomfort. I am a bank employee so it involves lot of sitting through the day, mostly I dont exercise much. I'm 42 years old and weigh 60kg. I'm a vegetarian. Is my problem hard stools only or internal hemorrhoids ? Is there any cure for it through food and lifestyle changes ? Does this condition require surgery ? Please suggest remedies, thanks