KNCPARKS, your description of being unable to unhitch sounds like you are putting upward pressure on your hitch latch before opening the latch. However, others here also mention putting stackers under 'the wheel' in a way that leads me to believe that they are referring to a wheel attached to the tongue jack. Especially when the tongue jack has a wheel, the following order minimizes the risk of movement that can go bad: 1. Chock the tires front and back. 2. Unlatch the tongue (leave safety chains on in case of movement). 3. Raise tongue off of ball. 4. Push and pull on camper to assure some stability. 5. unhook safety chains. 6. Level front to back.
Others here use blocks under the wheels to obtain side to side level, and that requires some estimate of the amount of lift needed from the unlevel position. Those blocks are fine and inexpensive. However, if you don't like that process, there is a handy little leveling tool called a BAL Leveler that allows you to raise one camper tire with fine adjustments, all without having the trailer on the hitch. I have found that to be a handy tool when setting up alone. Here is a link to a video that illustrates: