Android App, Simple Visitor - expert messaging App

I need a beautiful and simple messaging mobile App, Visitors features: 1. from home Ask Anything, choose category/sections (e.g psychology, marriage, business, tax etc) 2. Get App notifications when there is reply. 3. View all responses for my single question. (Visitor so each question create a conversation between visitor and expert) 4. View all my queries/questions I asked 5. No signup, no username or password. 6. Visitor register PIN for privacy, when lock the App no one can view details until unlocked by entering PIN 7. Setting PIN is optional, can not limit visitor from sending question. 8. User can reset own PIN, a secret question and answer can be used for security reason or old PIN Expert features.( Web admin ) 1. Get notification by email, when there is new question 2. Can add/edit or remove question categories 3. Can add more experts and assign one or more categories 4. Expert registration (full name, username, password, assign one or more question categories) 5. Expert view/reply on questions belonging to assigned categories. 6. Need to login 7. Expert can reset own username and password 8. admin can reset any expert's account 9 View questions, filter by status (waiting experts, responded) 10: Admin only can send public message to be viewed by all persons with App (admin can send a notice or announcement to all app users) this is like a motivation notice in to appear within the App home. General feature.. 1. Modern and Social Design 2. More conversation interactive especially between question posting and expert responses 3 Post Question can contain text, image, link url or video link. no video upload. 4. Other suggestion. .................................................. After android Android, we will discuss for iOS engagement. we just start with android Please share me your related / similar works and technologies used