Drawing with the Line Tool

Help please.

i figured out how to re-draw my original image shape using the (line tool) and get it into the shape i want with my original image locked… my line drawing which is on a seperate layer is an exact replica of my original yet i cant get it too fill with colour i have tried the fill small gaps medium gaps large gaps and it still doesn’t fill…i have checked my line art and i cant see any gaps in it.i found a video tutorial for the line art and followed it if i can get the image too fill with colour then thats everything i will need.

Can anyone help.