You shouldn't put any personal information like your serial number on a public website like this one.
Make an appointment at the Apple Genius Bar for service after the stores re-open. If you need to find an Apple Store - Find a Store - Apple. Also, see How to find your nearest Apple Authorized Service Provider (AASP) or Distributor (AAD). You may also get Apple authorized service at a local Best Buy.
Contacting Apple Customer and Support Service
- Apple Store Customer Service at 1-800-676-2775 or visit online Help for more information.
- Primary support help at Contact Support.
- To contact product and tech support: Contacting Apple for support and service including international calling numbers.
"Your Apple-branded or Beats-branded hardware product (“Product”) is warranted against defects in materials and workmanship for a period of ONE (1) YEAR from the date of original retail purchase (“Warranty Period”) when used in accordance with Apple`s user manuals (refer to www.apple.com/support/country). Under this warranty, you will be able to direct your claims to Apple even in situations where you purchased the Apple Product from a third party.” [Apple One (1) Year Limited Warranty – Accessory - For Apple and Beats Branded Products Only.] You get 90 days of free telephone support from date of purchase of your Apple device. You should use it.
Using Activity Monitor
Use Activity Monitor on your Mac
Runaway applications can shorten battery runtime, affect performance, and increase heat and fan activity.
Using Activity Monitor Part 1- CPU and Memory
Using Activity Monitor Part 2- Energy, Disk, and Network
Please read Writing an effective Apple Support Communities question. We are here to help. We are all users. We are not mind-readers nor clairvoyants. We only know what you write down and tell us. Be specific and thorough. Include your hardware information and installed version of macOS. Try to write clearly. Think about what you want to say before you write it down, then re-read it to see if it makes sense.