Difficulty with penetration while other touch feels fine is often linked to vaginismus, where the vaginal muscles tighten involuntarily, rather than an actual narrowing of the canal. It is a common, well recognised condition and a very treatable one, not something to feel embarrassed about or blame yourself for.
Next Steps
A gynaecologist can examine you gently to rule out any anatomical cause and confirm if this is vaginismus. Pelvic floor physiotherapy with gradual dilator exercises works well for most women with this.
Health Tips
Please don't delay a visit to a gynaecologist out of embarrassment, this responds well to treatment.