It could be that an evil spirit (demon) is blocking your relationship with Jesus Christ. There are 15 doors that open us up to the enemy of our souls and prevent us from deep fellowship with Jesus. This article will shed light on the subject.
No. This is a bad translation of the greek word diamonizomai, which means "under the influence of". So, we can come under the influence of demonic powers; however, we cannot be possessed. This two page list of problems may indicate the possibility of the influence of demons; however, it does not indicate that you are owned by the demons.
Memories can be healed. Jesus came to heal the broken hearted. So, if experiences of your past have damaged your heart, your memories, you soul, in any way, they can be healed by Jesus in the power of the Holy Spirit.
[Answer goes here]
[Answer goes here]
[Answer goes here]
[Answer goes here]