The lump on her chest is most likely a full crop. If you palpitate it, does it feel like a firm bean bag.... ie a bag full or particles?
 
As regards her comb being pale and flopped over. That might depend on her breed... my leghorns and legbars have large floppy combs that are more pink than red and hang over one eye whereas my RIR and Marans have a very scarlet upright comb. If your hen's comb used to be scarlet and now it is pale, then you may have a problem with red mites or internal parasites(worms) causing anaemia. Red mites hide in crevices in the coop during the day and creep onto the hens at night and suck their blood. If you get a brush and a dustpan and sweep any crevices at the ends of the roost bars onto the dustpan, you will most likely see red mites if they are the culprit. If you squish them, you will see blood. It is the hens blood that actually turns them red. I dip a soft brush in Diatomaceous Earth (DE) and use it to dust all the cracks and crevices during the day when the hens are out, but make sure to wear a mask as the dust is harmful. 
If it isn't red mites and you haven't wormed your hens recently then it might be worth doing that.
 
Good luck with bringing her back to prime health.
 
Regards
 
Barbara