karma is a blockage to your ambitions, intentions and your goals, it happen to minority of people, its not true that all people do have karma, only the people who are born as seeker of the truth!
those people born with 100% blockage to their dreams, they cant manifest anything at early age, but fortunately it cease by years, at puberty karma will decrease to 75%, and estimably at the age of 33 less than 25 % of the blockage exist, those people will see life going easier and easier by passing time, till the person is pure and have 0% blockage, at this time he/she can manifest dreams and goals easier.
at each segment of those people life they clear some of the negativity, which is specific to each person according to their life, jobs and dreams, usually the negativity is loaded to important things in someone life, love and relations, job, and domestic things.
at the moments of clearing he/she will experience emotional blue (easily recognized by the self ) accompanied with manifesting bad events, the exact opposite of what he /she wants ( this opposition will cease by time leading to self development regarding relations and work ).
at the time of clearing the person will be isolated depressed and living in quarantine of thoughts and recurrent pattern.
the body has a memory inside, codes loaded by the person intentions,emotions and passion, this is the positive codes ( or positive energy ) and as a response the body create blockage ( total opposite to the positive codes ) when the negative codes released, they manifest the bad events and the bad emotions, but when its finished there will be ease and more peace and freedom.
since those bad codes written in someone body, they may cause minor body symptoms when they are released, but those symptoms are minimal and trivial and can be easily tolerated, symptoms like minor flu, or skin rash or diarrhea, those people can recognize the reality of those symptoms and they know (feel) the symptoms are not that serious, they will not seek doctors, they will just let go.
this experience is very rare, and those people are little bit different in attitude and the way they like to have things done.
its very important to stress that this is very rare and only a minority of people will have it, so if you feel that you have this unexplained blockage, just believe yourself and believe in yourself.