fix or track with self employment

Hello

I am going to have to remortgage soon and am very confused: not sure whether to fix or go for a long term tracker. I have 20 years left on my mortgage term. To complicate things further, i am considering going self employed within the next year. I'm worried that if i go for a 5 year fix (stability) now rates may be going up (?) when that deal ends and plus i may be self employed then. I have heard it's more difficult to get a mortgage when you are self employed. Is this true? If i am going to be self employed in the next year or so (i am currently employed), is it better to go for a long term fix or track? Sorry about my rambling..any help would be appreciated. Thank you