Pichu evolves by happiness.
pichu does not evolve at a level,it evolves with a high friendship.Pichu can evolve at any level if it has enough friendship.
pichu evolves by friendship so when it likes you enough it will evolve no it dosent it evolves at level 20
sentret evolves at level 20 in Pokemon heartgold
Ampharos does not evolve in Pokémon HeartGold.
Level 15.
level 20
level 31
Level 30.
level 30
Level 36
when it has high friendship
it evolves at lv.59