Physical: birth, old age, sickness, death.Mental: separation from someone/ something you love, contact with someone/something you dislike, not being able to achieve your desires.
(1) Ordinary suffering - dukkha-dukkhata (emotional, physical and mental suffering).(2) Suffering through change - viparinama-dukkha (suffering that happens through the impermanence of things).(3) Suffering through dissatisfaction or attachment - samkhara-dukkha (suffering due to being attached to objects, people and the things you do in life).
Kisa Gotami's child died young leaving her devastated. The Buddha told her she should visit all the houses in the village and ask for a mustard seed from any house in which no one had died. She could not find such a house and eventually realised that death is inescapable and buried her child. The idea that everyone experiences suffering and an awareness of impermanence reduces suffering and makes it more bearable.
"But what is a chariot? Nagasena asked. Is it the wheels of the axies, or the reigns, or the frame, or the seat, or the drought pole? Is it a combination of those elements? Or is it found outside those elements? The King answered no to each question. Then there is no chariot! Nagasena said." Milinda Panha. The term 'chariot' refers to all the parts, so a person exists from all the parts they are made up from, there is no separate 'self' independent from these parts.