Devar Eliyahu: She'elasi is a small matter, not of the body, e.g. money, a house, items... One can request this also from people. Tikvah is something that one may request only from Hashem - "Al Tivtechu bi'Ndivim." It can apply to the body, for He can do anything. Who can give to me what I lack in property and animals. Tikvasi is a cure for my body and [restoration of] my children. Iyov held that this is hopeless.

Malbim: Elifaz said that if I accept the afflictions, Hashem will cure me. I hope only for death - if only Hashem will hear my request and grant it!