Add MaintainScrollPositionOnPostback="true" to page directive. This will keep your page at the position you scrolled after postback
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="CourseSubject.aspx.cs" Inherits="BBCApplication.Students.CourseSubject" MasterPageFile="~/Site2.Master" MaintainScrollPositionOnPostback="true"%>