Data using session object doesn't display on Page_Load

I'm using SQL/VWD 2005 Express and have a TextBox into which I want to pull some records from the db when the page loads.
The problem is that the text doesn't display when I first hit the page. 

If I click one page deeper, then come back, the text displays.
(Maybe I'm trying to use a session variable too soon in my query?)

What am I doing wrong here?

On page A, I send the user to page B and pass name/value pair in the querystring (called claimID).

On page B, I look for that in my master page and set a session variable:
 
protected void Page_Load(object sender, EventArgs e)
{
if (Request["claimID"] != null)
{
Session["claimID"] = Request["claimID" ...