Dead Island Side Quests Walkthrough: Tell me where it hurts

You get the "Tell me where it hurts" sidequest from the lighthouse area.

First, talk to James who will ask you to help people around the lighthouse. Then, you can go talk to Mick Fler who will give you this quest.

Mick wants you to find a bottle of painkillers and 3 bandages for Linda.

Check your inventory. If you have done enough looting, you might already have these supplies, in which case all you have to do is give them to Mick. Otherwise, you need to go find these items.

You can find painkillers in the infirmary, after clearing the zombies while doing the "Bloody Health Service" side quest for Dr. Jack. For bandages, try looking in the wrecked ambulance lifeguard truck on the road between the lighthouse and the lifeguard station. There's also a paramedic bag which is needed for the "Life in a Bag" sidequest.

Or, you can just go loot the hell out of stuff until you get the supplies you need.

Another option is to check with the merchants in the lighthouse or lifeguard tower, to see if they sell those.

Once you have the painkiller bottle and the bandages, proceed back to the lighthouse and deliver those to Mick. This will complete the quest.