Experiencing pain during sex is not something you need to live with. Vaginismus usually has psychological factors that cause it, good news is you can learn how to treat it.
Premature ejaculation is a very common sexual issue for men to face at some point in their life. Sex therapy can help uncover what causes it and how to manage it depending on the individual.
Not being able to orgasm or having troubles is very common for women. Maybe you have troubles both during penetrative sex, and clitoral stimulation.
It is common for a man to experience erectile dysfunction (impotence) at least a few times during his life. Factors can be biological and psychological. Sex therapy plus medications in some cases can yield great results.
If you and your partner like different things in the bedroom, it can be hard to know how to please one another.