Two conditions readily come to mind.
The first is that of obstructive sleep apnea, which is when breathing pauses while asleep due to an airway that is too narrow or blocked. Choking in sleep is caused by your airway being blocked by soft tissue in the neck. When air cannot reach the lungs effectively, it causes you to wake up suddenly choking..
The second condition is that of a panic attack. Nighttime (nocturnal) panic attacks can occur with no obvious trigger and awaken you from sleep. As with a daytime panic attack, you may experience sweating, rapid heart rate, trembling, shortness of breath, heavy breathing (hyperventilation), choking sensation, flushing or chills, and a sense of impending doom.
Do seek treatment from a mental health professional who has a special interest in sleep medicine as he can evaluate your condition further and order a sleep study if it is indicated.
