It is very well known that many fears and phobias or emotional problems come from past lives. The classic example being having a fear of water which came from being drowned in a past life.
However, there are many more emotions that can come from past lives. Examples are the following:-
Obviously not every emotional problem comes from a past life, but if you have tried to reduce the negative feelings in other ways, and nothing has worked, then it is another option to try. Other clues that could indicate are feeling the emotions very strongly in dreams or feeling the emotion very strongly just being around someone, even if they have not said or done anything.