Your nipples might be sore now but that does pass. If hunger isn't the issue- why offer top ups, you know? Cluster feeding is very normal in the first few months.
Your supply is also not fully established at 5 days post partum- your milk is really only just in. Replacing feeds with bottles at this pint can damage or inhibit your supply unless you pump at the same time as the feed- and your body responds to the pump really well.
If the pain is just simple tenderness, it's worth trying rite aid gel pads and using lansinoh to soothe you. If your nipple is coming out squashed or ridged right after a feed, or is grazed or split- you have a bad latch that I would recommend you get help for before throwing artificial nipples into the mix- can you access an IBCLC?