The purpose of this study will be to compare the efficacy of adding hydrocortisone phonophoresis or iontophoresis on pain, function, range of motion and shoulder external rotation isometric strength in patients with subacromial impingement syndrome.

Routine physiotherapy has been advocated was an effective treatment for SIS. However, there is lack of best exercise treatment and lots of studies are under consideration. According to published data focused on management of shoulder pain, it looks like that therapeutic exercise is not sufficient to treat SIS and it is compulsory to combine with other remedies to get the best results

Inclusion Criteria:

1. All patients were diagnosed as unilateral SIS with stage II Neer classification > 3 months.
2. Positive impingement sign (Neer's test or Hawkins-Kennedy test), / painful arc during active arm elevation, pain or weakness with resisted isometric external rotation or resisted scapular plane abduction with the humeral internal rotation (empty can test)
3. The age of patients ranged from 18 - 60 years old.
4. Both genders will be involved.
5. Shoulder pain scores more than 5 on a numeric rate scale for pain of 0- 10.
6. Failure to respond to conservative NSAID.

Exclusion Criteria:

1. Frozen shoulders.
2. Arthritis of the shoulder.
3. Shoulder instability.
4. Pregnant women.
5. A pacemaker.
6. Previous shoulder surgery.
7. History of dislocation of the shoulder.
8. Internal metallic fixation.
9. Malignancy.
10. Previous corticosteroid injection.
11. Rheumatoid arthritis
12. Partial or Full thickness tear of the rotator cuff.
13. Cervical radiculopathy.
14. Physiotherapeutic shoulder treatment within the last 3 months.
15. The patients will randomly be assigned into 3 equal groups, 20 patients for each group.