Answer: These are the right answers:
1. era
2. quería
3. estaba
4. tenía
5. iba
6. jugaban
7. eran
8. le dolía
And this is the right order: 7, 6, 3, 4, 8, 2, 1, 5.
Explanation: Just to elaborate a little on the answer, it can also be added that the imperfecto is used, among other uses, to express actions in the past, as it is the case here. Miguelito hurt himself playing baseball and he went to the doctor. For regular verbs (querer, jugar) you must add the following endings: -aba, -abas, -aba, -ábamos, -abais, -aban (verbs in -AR) and -ía, -ías, -íaíamos, -íais, -ían (verbs ending in -ER and -IR). For irregular verbs (ser, ir) you have to learn their specific endings.