Hello, I would be happy to help you with your question.
First with regard to the endometrium - this is the part of the uterus
that grows and sheds each month. At its thickest, towards the end of your cycle just before your period, the upper end of normal is about 14mm. 16mm MIGHT be considered thickened depending on the reasons for the scan. If the scan was for abnormal bleeding, then the finding is significant. If the scan was done for other reasons, then it is probably a normal finding.
With regard to the ovarian cyst
, a 3.6cm cyst that appears benign is not that significant. If the scan was done for pain related reasons, then this might explain the pain. The usual plan is to followup this scan in about 8-12 weeks.
If there are more details you can provide it might be helpful. Otherwise, I hope this answers your questions!