Go back to your variable creation, and change all your variable creation to Cap{#}.
Example:
Cap1 = [ 1 2 3 4 5] ==> Cap{1} = [ 1 2 3 4 5];
Cap2 = [ 1 2 3 4 5] ==> Cap{2} = [ 1 2 3 4 5];
Cap3 = [ 1 2 3 4 5] ==> Cap{3} = [ 1 2 3 4 5];
...
Then you can do your loop like:
for j = 1:length(Cap)
plot(Cap{j});
end
You're facing difficulty now because you've named your variables incorrectly like Cap1, Cap2, etc. Read this: