Issue pressing down French Press I haven't had this issue happen often, but its been a few times. When I make French Press coffee my steps are to:

Boil water

Put coffee grinds in French Press

Pour hot water in

Stir coffee grinds in the water

Place the lid on top

Wait 3 1/2 minutes and then press it down.
Once in a while when I go to press it down, it just doesn't want to press. There is so much pressure resisting underneath. The one time I kept pressing, the coffee and grinds shot out the top and burned me. It seems as if too much air gets trapped underneath but I don't know how. Does anyone know why this happens; if I am doing anything wrong that causes this?
A number of things aren't clear from your question. I can think of three issues that might result in the problem you're having.
Clogged strainer
If the strainer is clogged, the air has trouble being pushed out. That may make it harder to push it down as the air stays under your strainer.
The solution is easy, make sure the equipment is cleaned well, a bit of soap does wonders to remove oily residuals.
Equipment
You may be using large equipment to make a small amount of coffee. That way, when you're pressing down the strainer is already near the bottom of your container meaning you cannot press much further. To solve this, try using a container of an appropriate size. If your French press is filled at least halfway at step 4 then this shouldn't be an issue, if it's much less, consider making a larger batch or using a smaller French press.
Blooming
Blooming is technique for letting gasses (mainly carbon dioxide) escape the coffee beans. I don't think this is what causing you trouble, but I think it's worth mentioning. To get a good bloom, you just need to take some time between step 4 and step 5. After stirring the beans, you wait 30 to 60 seconds to allow some of the gasses to escape.