could you please tell me what the matter is with you是不是病句？

是病句
应该是could you please tell me what is the matter with you
what作主语，语序不变

宾语从句的语序错了，应当是could you please tell me what ist he matter with you

不是病句。
what the matter is with you作tell的宾语从句，用陈述句语序。

could you please tell me what is the matter with you

what is the matter with you和你有什麼关系?