The context suggests pain related to eating. A 'stomach ache' is common after eating too much.
Answer: stomach
A serious condition requiring hospital attention is usually an 'illness'.
Answer: illness
After an accident, a leg could be 'broken'.
Answer: broken
Dentists 'treat' patients with dental problems. 'Care' is too general. 'Experience' doesn't fit. 'Throat', 'stomach', 'illness', 'broken' are irrelevant here.
Answer: treat
Working with sick people can be a rewarding 'experience'.
Answer: experience
The word 'care' is not used in any of the sentences.