The most common reasons for pain when inserting medication into the vagina are as follows: 1. The vagina is inflamed and the mucous membrane becomes congested and edematous when the medication enters the vagina. 2. The pain occurs when the nails are scraped against the vaginal wall because the nails are not cut short when inserting medication into the vagina. If you have pain when using the medicine, cut your nails short and then gently insert the medicine into the vagina along the vaginal wall to reduce the pain. If the pain is caused by inflammation, the pain will disappear naturally if the symptoms improve with continued use of the medication.