yes, thank you for pointing this out!
I didn't know each address has it's own unique private key and I only exported private key of first receiving address (I assumed that this private key will give me access to both receiving addresses)... Now I clicked on second receiving address and I exported private key for that address and this key is different then the first key! so I imported this second private key to Electrum and now I see my balance and history!
Thank you for explaining me these basic concepts... I HODL since 2013 and I still learn basics

Thank you BitMaxz, NeuroticFish, jackg for helping me! You guys make this community great!