Well I can certainly relate to your problem anyways!
In my opinion it is related to the fact that I am disconnected from my own emotions , for example when my grand father died , I went to the funerals , in this case of scenario you are supposed to cry right ? Well I just didn't feel a single thing and it hurts me to say that because I loved him although we didn't talk a lot together... Well the point is there are no emotions occuring and I believe this is because we've become totally "immune" to the stimulis and therefore we can't feel anything!
Do you have this problem as well ? ( not feeling emotions "flowing" in your body )
We are all different and unique in a way so I can only give you my point of view on the topic , but eventually you will find a way to become more affectionate with the people around you don't worry