what's 'hypofunctioning nodules', on my nuclear thyroid scan?

i got a hyperthyrroid diagnosis then got sent to get a technetium scan. the report says 'findings consistent with hyperthyroidism SECONDARY to Graves or toxic phase of Hashimoto's. small HYPOFUNCTIONING NODULES in left & right lobes...'
i now am on carbimazole. that's going pretty good.
but what's this 'nodule' stuff? what's it mean..?
% uptake was 4.98 [normal 1.1 - 4.0%].
i know it was a while ago, i'm just back tracking to get as much info together to find out more about my condition...