Consider:

Where appropriate, increase statin dose
Consider ezetimibe, if maximum-tolerated statin dose fails to achieve target. Or, as monotherapy, where low-dose statin therapy not tolerated.
If ezetimibe monotherapy fails to achieve target, refer to local lipid guidance.

Common

Medication-related

Other

* Hyperlipidaemia in pregnancy is usually normal. Avoid measurement unless advised by specialist.

Are symptoms likely to be caused by the statin? Did they pre-date the statin? Systemic? Single joint or focal muscular pain is unlikely to be statin-related.
Are there pre-disposing factors or other causes e.g. alcohol excess, poorly-controlled hypothyroidism, frailty, drug-drug interaction (see BNF)
Most patients tend to tolerate an alternative type or dose of statin, and it is often worth trying several different statins until a tolerated agent is found.
Atorvastatin and rosuvastatin give the largest cholesterol reductions. But use of less potent statins, if necessary in combination with ezetimibe, will also reduce CV risk.

Where a statin is not tolerated, consider:

Stopping the statin for 4 to 6 weeks, and restarting once symptoms have resolved
An alternative statin with similar cholesterol-lowering efficacy e.g. rosuvastatin 10 mg instead of atorvastatin 20 mg
A lower dose (such as rosuvastatin 5 mg, or atorvastatin 10mg). These may also be prescribed on alternate days.
A weaker statin e.g. pravastatin 20 mg (but more likely to require ezetimibe as adjunct)
Ezetimibe - either in combination with a statin (where LDL-C remains far from target), or as a monotherapy (where multiple statins have not been tolerated)