Anorgasmia is the medical term for regular difficulty reaching orgasm after ample sexual stimulation. The lack of orgasms distresses you or interferes with your relationship with your partner.
Orgasms vary in intensity, and women vary in the frequency of their orgasms and the amount of stimulation needed to trigger an orgasm. Most women require some degree of direct or indirect clitoral stimulation and don't climax from penetration alone. Plus, orgasms often change with age, medical issues or medications you're taking.
If you're happy with the climax of your sexual activities, there's no need for concern. However, if you're bothered by the lack of orgasm or the intensity of your orgasms, talk to your doctor about anorgasmia.