COVID-19 Symptom and testing

Hello, I am a student studying in the UK. I would like to know if I could get a covid 19 screening. I have been monitoring my condition for the past 14 days.

10/3/2020 - I had fever, runny nose and sore throat. I can barely do anything. I feel tired
11/3/2020 - The fever and flu is getting better, but the cough is worse
12/3/2020 - I have recovered from everything
19/3/2020 - I had fever but not as bad as on 10 March. I can still do stuffs like cooking. No runny nose. Just cough (berkahak)
20/3/2020 - dry cough, recovered from fever
21/3/2020 - recovered
23/3/2020 - I arrived in Malaysia. I was okay when I was at KLIA, I can pass the thermal screening in KLIA. But when I get into the car, I started to have fever but not that bad.
24/3/2020 - I cough quite a lot

May I know how do I know if I have breathing difficulties? Do I feel short of breath or do I feel chest pain when breathing. I am not sure whether I am just being paranoid but I do feel uncomfortable when breathing on those days that I was sick. I feel like I need to put an extra 20% effort to get the normal amount of air into my chest. When breathing, I could feel that my chest is expanding literally (normally when we breathe, we wont even feel the motion of our chest and tummy)