YOUR WORST FEAR STARTED LONG BEFORE YOU GOT HERE. If you have a fear that you just can't seem to get a handle on, if your fear seems unreasonable even to you, or if you have an uncontrollable response to a specific thing, then it may be time to look to a past life for the reason.
I've done many past life readings, and one question that I usually ask before doing the reading is whether the person has any fears that they can't get past. If they do, I'll look for the situation in the past life that caused this fear in the present. Most of the time, when a person connects with the original cause of the fear, they can understand and release it. Fear holds you back from reaching your fullest potential, so it's super important that it's released so that you can keep moving forward with your life and your spiritual path. By finding the cause, the fear loses its hold over you and the negative fearful response is replaced by positive understanding.
Here's an example. In your past lifetime, you were asleep in your apartment, and a fire broke out. It was dark, in the middle of the night, and the fire alarm in the building didn't go off. You couldn't get out in time, so you perished in the fire. In your current lifetime, you're deathly afraid of fire, not finding your way/getting lost, or small spaces. Remembering this past lifetime can help you release the fear of fire, small spaces, the dark, smoke, finding your way/getting lost, or anxiety associated with sleeping. Sometimes the effects are instant, but it usually takes time for you to completely let go of the fear so that you're not afraid anymore. In this example, you may not like being around fire or small spaces, etc., but you won't be deathly afraid of them, either.