sometimes

He feels sometimes lonely.
He sometimes feels lonely.
Sometimes he feels lonely.
He feels lonely sometimes.

The adverb of frequency sometimes can go in three positions:

• Before the main verb: ‘He sometimes feels lonely.’
• At the beginning: ‘Sometimes he feels lonely.’
• At the end: ‘He feels lonely sometimes.’

When sometimes is in mid position, put it before the main verb: ‘He sometimes feels lonely’, not ‘He feels sometimes lonely.’

See ALWAYS