By the way, I'm just using a normal 55mm lens for my video. While I pan in the forest, it's blurry. Is it the lens or shutter speed that I should use/change? Does that have to do anything with my setting of 720p?
Depends on a lot of things: Is your aperture narrow enough to keep a deep depth of field? Is your shutter speed 1/125 or higher? Is the lens focused properly? Is the lens a good quality lens? And perhaps most importantly... How fast are you panning?
With settings of say, f16, 1/125, properly set focus, and a slow pan speed, the shot should come out pretty sharp. Of course, this all assumes bright sunlight or adequate light. If you're in a dark forest, then jacking up the ISO too high can introduce softness.
Also, what picture style are you using? If using Neutral (recommended), then there is no in-camera sharpening being applied. You need to add sharpening in post production.
720p really has almost nothing to do with a blurry shot.