I feel bad for Tori, because many thought she had a bad boob job, but instead she suffers from a condition which has caused this. Can't be nice for her having so many comment on her appearance.

'I get comments like that for years saying 'Fix that thing between your boobs.' or "what is it, it's like a gaping hole? Tori began. 

'It's actually a bone thing, it's called pectus excavatum,' she continued, referring to a chest wall deformity, also referred to as 'funnel chest'' per University of Utah

In this condition, the sternum and several ribs grow inward abnormally, creating a noticeable indentation — almost resembling a bowl in the center of the chest, according to the outlet. 

Tori Spelling proudly parades her bikini body at 51 after finally revealing the REAL reason for the 'gaping hole' between her boobs | Daily Mail Online