Hello, I Have Been Getting The Odd Whitehead Right On

Hello, I have been getting the odd whitehead right on my collar bone just on the right hand side lately I have four of them and I tried not to pick but after a week of horrid whiteheads I picked and now they are just red angry scabs... wanting to know what might be causing these and why they take forever to heal?I get pimples on my face around my chin area every menstrual cycle but these collar bone ones are new