Hi Giandor, Thanks for writing your query. Symptoms of dizziness, nausea, cold sweats on experiencing severe pain can be due to Vaso-Vagal attack. In this, the blood flow to the brain decreases, resulting in decreased supply of Oxygen to the brain and the above symptoms appear in the beginning, which later result in unconscioussness. Symptoms increase in sitting or standing position while the symptoms disappear on lying down. This is because on lying down, the blood flow increases towards brain leading to relief from symptoms. Lying with head end low will be more beneficial. Orthostatic training exercises can be helpful in preventing the recurrance of the attacks. You can consult your doctor for examination and recording of your blood pressure and other vitals along with investigations for finding the cause of rectal pain. I hope this is helpful to you. Thanks.