Haven't seen my Mum since I was 5.... My Father won't let me see her. What should I do?

you're not being selfish, you grew up without a mother and now you just wanna go look for her like for once, probably your dad is just worried that you'll leave him or something... and he probably still hold grudges towards your mum. maybe you should check out with more people (aside from your dad), how your mum is like.