Hello Thanks for writing to HCM You are suffering from irritable bowel syndrome.It is not related to lightheadedness and headaches. You need few investigations like routine hemogram,LFT,Stool test(routine and culture),ultrasound of abdomen.Further investigations can be done if needed. Irritable bowel syndrome is disease associated with large intestine and exact etiology is not known. There is no specific treatment of this disease. It can be controlled by altering diet pattern,psychological therapy and medicines. You should take plenty of fibres in your diet in the form of salad etc. If you have lactose intolerance you should restrict it. Laxative and antispasmodic can be used. Low dose tricyclic antidepressants are also useful. You should do regular exercise and try to reduce stress in your life. You can also take tablet loperamide SOS. You should avoid cold drinks and high gas forming vegetables like cabbage and cauliflower. You may need psychological counselling if needed. Get well soon. Hope I have answered your question. Take Care Dr.Indu Bhushan