The shooting pain which lasts for short duration are of neurological origin. All investigation in rectum, anus and in vagina will be normal. Colposcopy
may not be helpful. You may need an MRI of spine to rule out any compression of spinal cord
or nerve root
which may cause the pain. A spine surgeon
must be consulted for your relief. There is nothing to get embarrassed to convey your symptoms to a doctor. All the best.