Handlebar height adjustment

Hello all
I won a Trek 820 over the winter and have just taken it out for the first
time. I've adjusted the saddle to a nice height for my legs but I feel like
I'm leaning to far forward. I get pains in my shoulders and neck after about
15 minutes. I'm pretty sure the 18" frame is a good size for me so I wonder
if there is a way to raise the handle bars a few inches? Do anyone have any
suggestions?

Thanks in advance...
Marco