幸福，快乐，轻松，舒服 what are the difference?
幸福，快乐 means happy.
Can I replace one of them in the same situation?
放松 means relaxing, not worry
放松 is apposite with 难过，紧张，辛苦？
舒服 is only used when I mean my health is good, I feel comfortable.

I am confused with all these words.
If you can explain or give an example sentense for me, I am really appreciate it.

用中文或者英文解释都可以。
谢谢大家：）

Question

幸福，快乐，轻松， 舒服 what are the difference?
幸福，快乐 means happy.
Can I replace one of them in the same situation?
放松  means relaxing, not worry
放松 is apposite with 难过， 紧张，辛苦？ 
 舒服 is only used when I mean my health is good, I feel comfortable.

I am confused with all these words.
If you can explain or give an example sentense for me, I am really appreciate it.

用中文或者英文解释都可以。
谢谢大家 ： ）

Answer

You're correct. 幸福，快乐 both have the meaning "happy". 快乐is a generic description, but 幸福 is usually to describe love, a marriage or family. 幸福also imply "satisfaction about life"
example:
她有一个幸福的家。 She has a happy family.
家人的关怀，我觉得很幸福。 Because of the love and care from my family members, I feel so happy.
我有一个快乐的回忆。I have a good (happy) memory.
you can always replace 快乐 with more specific 幸福 to indicate it's love/family related.

放松 is apposite with  紧张. ( relax vs nervous )

辛苦 means feeling hard or painful ( either mental or physical )
他的工作很辛苦 His work is tough.
他生病了，很幸苦 ( He got sick, and he's very painful )

难过means feeling sad about something.

舒服 = feeling good / relax / comfortable
不舒服 = uncomfortable / feeling ill ( either mental or physical )

Answer

简单的和你说说舒服吧，舒服有两种意思，一种是身体上的舒服，沙发很软，你坐着很舒服，身体没有不适应，另一种是心灵精神上的舒服，沙发很软，你很满意，精神得到了放松，产生了一些快乐的情绪