protected void Page_Load(object sender, EventArgs e)
{
Context.Request.Browser.Adapters.Clear();
Response.Cache.SetExpires(DateTime.Parse(DateTime.Now.ToString()));
Response.Cache.SetCacheability(HttpCacheability.Private);
Response.Cache.SetNoStore();
Response.AppendHeader("Pragma", "no-cache");
}
add this in your both the pages it will clear the cache.And by clicking on the back button you will get fresh page from the server.