Yes, if you wear too much contact lenses, you may get the ptosis. In adults, ptosis is usually the result of advancing age, but it also cause by some human reasons. Long term contact lens wear can cause ptosis. This is due to stretching of the muscle caused by repeated insertion and removal of contact lens. So, you need remember to less wear contact lenses.
It's hard to say. Eye symptoms can be caused by infection, irritation, or injury. Generally speaking, if your eyes don't have any problems, contact lenses would not cause ptosis. While you already felt something wrong with them, then your discomfort of your eyes may be caused by contact lenses, even your ptosis can due to wearing contact lenses. But contact lenses have a lower ratio of causing ptosis.