Rashbi himself taught that all positive attainments can be acquired through suffering. שׁלשׁ מַתָּנוֹת טוֹבוֹת נָתַן הקב"ה לְיִשְׂרָאל וְכֻלָּם לֹא נְתָנָן אֶלָּא עַל יְדֵי יִסּוּרִין (ברכות ה.) Rabbi Shimon said that "Hashem gave Yisroel three gifts, and all of them can only be acquired through suffering." These are Torah, Eretz Yisroel and Olam Haba. These three sublime pleasures can only come about through hardship.
Rabbi Akiva, the Rebbi of Rashbi, also expressed his belief that there are certain positive effects that can only come about as a result of suffering. The Gemara (סנהדרין קא.) tells us that when Rabbi Eliezer was sick, four chachomim came to visit him, Rabbi Akiva among them. The other three elders tried to comfort R' Eliezer in various ways, however Rabbi Akiva exclaimed חֲבִיבִין יִסּוּרִין, yissurim are beloved. Instead of distracting him from his awful pain, he put the pain into perspective. He expressed how precious pain could be, because as a result thereof one can merit to reach exalted levels.
Not in the Land of the Living
Especially in regard to Torah, Chazal tell us in many places that Torah can only be achieved through difficulty. Many seforim expound upon the concept that the only way to acquire Torah is through tzaar, through consistent toil and denying oneself the pleasures of Olam Hazeh.
The Midrash Tanchuma (פרשת נח סי ג') discusses this at length. It quotes a possuk in Iyov לֹא תִמָּצֵא בְּאֶרֶץ הַחַיִּים, the Torah will not be found in the land of the living. Chazal question the meaning of this possuk, will the Torah then be found in the land of dead? Chazal explain that the Torah, especially תּוֹרָה שֶׁבְּעַל פֶּה does not flourish by those who seek the pleasures of this world. The Midrash quotes the famous possuk (במדבר יט יד) זֹאת הַתּוֹרָה, אָדָם כִּי יָמוּת בְּאֹהֶל, This is the Torah, a person who 'kills' himself in the tent of Torah.
Chazal explain that Torah can only be acquired when one is מֵמִית עַצְמוֹ עָלֶיהָ, kills himself for her sake. This means he toils to a great degree, and abstains from engaging in various pleasures of the living, and in this way, he disconnects from the 'land of the living'. As a result of this mesiras nefesh, this voluntary suffering, he can truly grow in Torah.